McCoy has actually gone on record and stated that he feels his being in the TV movie was a mistake. As stated above, it does take up a lot of time, although the failed regeneration aspect of the movie is rather crucial to the story. However, if McCoy hadn't have been in it, I'm not entirely sure they would even count McGann's movie as canon! We'd have no knowledge of how 7 changed into 8, as well as 8 to 9 (in 2005, I mean). Thankfully, both RTD and Moffat have made sure it is canon, and rightly so.
Ermmm... Yes and No. No because, as others have said, RTD wanted to start fresh and new. With a new 9th Doctor, he could easily paint the Time War backstory around him. We hadn't seen the Doctor in a very long time, and there was so much story and character potential with the idea of this awful war having changed him. Plus, there would have been TV movie baggage to deal with at the time, which would have just confused younger viewers. Moffat doesn't have it so hard in this regard. The show is now so massive, and its new fans from 2005 (me among them) have extensively dived into the classic series, so Moff can give us an 8th Doctor mini episode and not have a chunk of the audience scratching their heads, but at the time the new series had to find its feet and make a name for itself on its own. A new Doctor, fresh to the show, was essential for that.
However, despite all that, it would have been awesome to have a McGann series. He knocked it out of the park this week, and I think he could easily sit among my favourite Doctors with someone like Moff writing for him.
Plus... while Eccleston was brilliant as the Doctor, and I loved the 9th Doctor's series, I'm really not a big fan of his attitude post Who, and I feel for McGann in this regard, as he clearly loves the show and rightly feels he was never given a chance to show what he could do, at least until this week. He even offered to film a regeneration scene when they decided not to get him back, which was very good of him in hindsight, showing he does genuinely care for the show and the role of the Doctor. The less said about Eccleston in this regard, the better.
But yeah. I suppose I'd have to go with no, but damn what a good series McGann might have made. We might not see him again on the screen, but never say never. He's not exactly an old man, and DW is going nowhere!