I don't think the problem lies with the story, the costume, Colin's performance, or making his introduction be the final story of Series 21.
I think the problem lies in people not not thinking critically and just reacting negatively.
Anti-80s bandwagon, of which even numerous DVDs for episodes of that decade sometimes unfairly reveal.
I've now made it through Attack of the Cybermen, which marks my first exposure to that eponymous race, and I was at first a bit put off by the fissures that existed early on in Part 1 between Six and Peri, especially coming directly off of him getting her to smile at the conclusion of The Twin Dilemma, Part 4, but things smoothed out as the story progressed.
I've seen some criticisms levied against the change in format from 4 25-minute episode parts per story to 2 45-minute episode parts per story and how the structure wasn't shifted to compensate, but as someone who came to the franchise through nuWho first, I honestly don't see why that's a problem.
I was a little bit underwhelmed by the character's of Stratton and Bates and was prepared to write the story off as being overstuffed in the same way that I felt The Caves of Androzani was, but the scripts eventually made their inclusion make sense.
It's my understanding that there was a lot of backlash in the 80s to the violence quotient of the story, which, with the context of having seen both parts of it, strikes me as odd given what else was out there in popular culture at the time and given the perspective of looking at things through a modern lens.
I did think that it was funny that Peri kept questioning whether or not the Doctor had stabilized, and thought that his realization that he might not be as stable as he kept insisting was played perfectly by Colin. I also loved the further glimpses we got beneath Six's OTT veneer into his compassion and heroism, particularly when he gave Flast the means to destroy the Cybermen and when he felt horror at having misjudged Lytton as badly as he had.
As both a Series Premiere story and my first introduction to the Cybermen, I thought Attack of the Cybermen was quite good and very reminiscent of nuWho, which, as a modern TV watcher, was nice.
I had no problem with it when I first saw it. Cyber conversion isn't going to be clean (nor cartoon campy, like NuWHO CGI), and Cybermen understand emotions and exploit them. This is the one story where WHO uses them most effectively. Earthshock and Tenth Planet being the other two contenders IMHO.
Colin, as usual, nails it as the Doctor. The violence works for this story and the 80s had violence all over the place. And was a trendsetter for some of today's shows in that regard.
Saward may have disliked Colin but it didn't stop him from writing the new Doctor with a robust mix of cynicism with compassion, and it's appreciated that he didn't overdo personal bias into the job too much as such. I can imagine where he or anyone could.
How could Flast remain in that cell and eat and live? How did she get in there and how long ago, back when this Cyber base was constructed? (is it that important?)
Sonic lance = sonic screwdriver party deux as Saward also destroyed the thing thankfully in "The Visitation". Now it's back, bigger than ever... oh, and purple. And glows when touched. More trendsetting. Unfortunately.
The Doctor must have known Lytton more offscreen, there wasn't enough onscreen treatment to show Lytton and the Doctor - but enough had been told in "Resurrection" that Lytton could indeed be nothing more than a paid mercenary. So it's a nice twist but Colin still goes into Davison-mode at the end. Final shades of the preceding predecessor persona in display. And Lytton is an inspired choice, as mercenary with a heart AND to show the Doctor being compassionate as a bridge of sorts.
Halley's comet was topical but not in a pompous way as well.
And as complex as it was, I didn't know at the time (or needed to) the previous Cybermen stories to understand what this sequel was trying to do. It had enough deft handling.
Still wish Stratton and Bates could have been more likable but we do see how they can lop off Cyber heads (conversions that failed!)
You're right, but in terms of The Twin Dilemma specifically and the original and continually perpetuated negative reaction to Colin, I think some critical thinking was sorely needed.
I don't think I've said this here, but while Christopher Eccleston's Nine was officially my "first Doctor", Colin's Six has become my favorite Doctor even after only 6 episodes plus one Regeneration scene because of how fabulously chaotic and layered he is.
"Twin" was a mess and with Eric having to fix so much and even effectively redo the final two episodes, ugh...

JNT was right in making Six so uneven - especially after Davison and Tom.
Stratton and Bates - yup. The making-of has Saward bringing up a great plot point but the characters themselves don't have enough to really latch onto. Griffiths had (and had some great comedy as well.)
I do wonder why "Attack" was made in part on modern day Earth, but it succeeds in being a sequel that loosely ties up old ends from eras that had no continuity, while being its own story without needing continuity to draw from in its own way.
Double-post again (sorry).
Here's my thoughts on Vengeance on Varos.
In the video retrospective/documentary that initially prompted me to delve into both "Classic Who" and Colin Baker's Sixth Doctor era, this story was singled out as a particular standout, and I have to say that, after watching it, I would have to agree with the sentiment.
I continue to really enjoy Peri and Six's relationship, which has settled into a kind of playfully argumentative status quo as demonstrated by their early scenes in the TARDIS but which is also full of genuine affection and trust as demonstrated throughout the remainder of the story once they arrive on Varos.
Narratively, the story doesn't come off as being nearly as dark and grim as 1980s audiences apparently thought it was, but it's still a very effective commentary on "reality TV culture".
Sil was an interesting antagonist who reminded me a little bit of the Face of Boe and Cassandra from the nuWho episode "The End of the World", although I was a little bit confused as to what happened to him at the conclusion of the story.
With 8 episodes and 3 stories under his belt, Colin has fully settled into character as Six, with his bombasity not being as pronounced as in both The Twin Dilemma and Attack of the Cybermen, thus allowing more of his heroism and compassion to shine through more overtly, although his witty quirkiness remains at full bore as evidenced by his remarks of "You'll forgive me if I don't join you" and "I think he needs more than water, Peri, eh?".
I'm still trying to work out my full rankings for the four stories I've seen thus far, but my initial instinct is to rank Vengeance on Varos as the second-best of Colin's era thus far, trailing Attack of the Cybermen, and is an episode that I would join the creator of the Sixth Doctor vid I mentioned - Richard D. Carrier - in highy recommending.
Six and Peri grew on me, though they needed more time to show the happy side of things. Both work well together thanks to Colin and Nicola, it'd be worse if they had actors without the screen chemistry.
Sil is just left there hanging, and what the Governor might do - we just don't know. Sil has his own animated story coming out in the UK in November on blu-ray BTW...
Six seems like a James Bond Roger Moore style Doctor with his quips. And a Craig-like Bond style in terms of violence if he has to do it.
Reality TV was there in a more primtive form but Vengeance does predict what has happened, in some countries, where people are humiliated or, in some cases, physically harmed, without knowing about it, for a thrill.
Can't wait to read your reviews for upcoming stories!