I watched this new version on iPlayer. I found the editing clumsily done with several key points removed (as others have mentioned), the inclusion of which would not have extended the runtime significantly. It's a worthwhile experiment, albeit not very well executed. I won't be buying the Blu-ray.
I think they're on the right track with the idea. It'd be fun to be a fly on the wall to see how the limits were placed with time allotment or other factors. Just enough key moments were removed... I recall Genesis of the Daleks was released in an edited format on LP in the 70s, Morbius was given a 60-minute truncated version on VHS, and Enlightenment and Planet of Fire getting omnibus edits on DVD. At least, prior to the DVD releases, people buying the condensed edits were wondering what was cut and were pining for the full-length versions. Now it's the other way around. It's hilarious in a way.
To be fair, especially with a long story, having to sit there and document scenes and decide what to take out is a bit of a lengthy chore. The tighter the net result (e.g. 75 minutes) makes it more daunting when you're going from ~168 minutes. One would have to watch it multiple times, and/or with an editor also familiar with the story and its progression, to confirm how the revised story flow progressed and hope that something springs to mind, such as "we need to keep that moment, what else can be shaved off?". There may have been deadlines and delays that rendered this a rush as well. The actual colorizing is amazing. The sound/music is competently orchestrated, even if it's either misplaced or trying to feel like the Cushing movie. The original, despite being slow in spots, did sell a buildup of mystery, fear and threat extremely well. Didn't bother me as a kid and that was in the late-80s when pacing was already faster than the standards set in the 70s.
I'll be buying it anyway; the original will be upscaled/enhanced for blu-ray and it'll be a while before the season comes out in full on blu-ray. hopefully there will be bonus features discussing how the colorizing was done, the how and why for tightening up a story, as well as other making-of tibits aren't included.