Trouble is some people have had it in for Moffat since he started (since before then if I recall correctly) so they're actually really glad there are no classic Doctors in the special. Let's be honest some people wouldn't be happy even if Moffat did incorporate every surviving Doctor and managed to resurrect the first three into the bargain, plus include every living companion.
Maybe you've been on a different internet than me, but it seemed like Moffat only lost his shine fairly recently for the vast majority of his detractors. People were very excited when he took over, they gave him the benefit of the doubt on the rough spots of his first season, chalked the issues with the second up to 'trying something different' and it was really only when he continued to make the same 'mistakes' through the third that the cries came up for him to move along.
Personally I think he is one of the best episode writers the show has ever seen, but in an editorial/oversight capacity he simply doesn't have the restraint to sort the wheat from the chaff before throwing it all on the table. Perhaps more importantly, the scheduling/production issues hint strongly at his being an artist that works best with deadlines and someone else making the important calls.
I do find it a bit strange, if not quite 'upsetting', that the original series seems to be getting the shaft a bit here. Tennant is all fine and dandy, but celebrating the 50th anniversary with just him feels like a bit of a cheat and if the original plan was in fact to have him and Eccleston then it looks like even more of a celebration of "nuWho" than the show as a whole.
This matches up with my recollection as well. Moffat wrote some great scripts for RTD, so people (in general) were thrilled when Moffat took over. However, it appears he's better at the artistic side than the business management side.
But, I've been enjoying Moffat's seasons greatly. No real complaints. Overall, I enjoy his work and RTD's work about the same amount, but for different reasons.
In the end, I wish there was a classic Doctor involved in the anniversary special. But, if not, I will likely enjoy it anyway. Still, it's a shame. These actors won't be with us forever and they contributed greatly.