(While we're talking about the old series, I'll also say that while having the Doctor regenerate without a prolonged coda may arguably be unfair to fans, it's also the norm. It may also be worth noting that if you remove the coda from 10's regeneration and have him regenerate immediately after sacrificing himself to save Wilf, it's almost identical to the way 5 regenerated in "The Caves of Androzani," which most longtime fans hold up the the best regeneration story the series has ever done. Here's the regeneration scene: http://youtu.be/qvAenK95PfQ)
(ETA, April 26: Coincidentally, I just happened to read a review of "The Caves of Androzani" that makes the point that Spectrox poisoning that ultimately forces the Doctor to regenerate occurs in the first of the four episodes, making the entire story a prolonged pre-regeneration coda. But my main objection to 10's coda wasn't that it was a coda, but that it was maudlin and redundant. (The latter especially, because the one part of the coda that worked for me was his visit with Joan Redfern's granddaughter, though that may have something to do with my feeling that losing Joan was a far more profound loss for him than losing Rose.) And speaking of 10, I'd be interested in hearing your take on the criticism of the RTD found in the comments. Start here—which doesn't mention RTD at all, but when that conversation starts, it's in response to that comment.)
Back on point, I think the show under SM is largely the same as it was under RTD or John Nathan-Turner or Barry Letts or Verity Lambert. The actors and props have changed, as has the storytelling style, but it's still the same show, which is why Doctor Who is so amazing. It's always changing, yet it's always the same. Not every storytelling/production approach to the series works equally well, but at the same time none of them have been complete failures nor unqualified successes.
But that constant change makes it hard to be a fan of! Especially, I think, for modern, ship-oriented fans. If your fanaticism is directed toward 10's relationship with Rose, any deviation from that will be viewed negatively (see, for example, the Hugo Award-winning "The Girl in the Fireplace," which Rose/10 shippers hate and nearly everyone else loves) and its disappearance could cause you to lose interest altogether. And it goes without saying that those fans would feel personally insulted if the new producer was less than wholly complimentary toward Rose. (Full disclosure: I thought Rose was a very good companion. Not the best ever—not even 10's best—but definitely in my top five. And while I don't know how SM insulted her, it's not that hard to find insulting things to say about Rose. I liked her, but let's ask Mickey Smith if she ever did anything that deserved to be insulted.) But it's not just a NewWho phenomenon; I know there were people who stopped watching when Tom Baker left. Or when the Doctor was stranded on Earth. 6 drove away a lot of people. It's an inherent risk when a show changes, and no show has ever changed as much as Doctor Who.
And I totally get that! Having been in situations where a change in direction or the departure of certain characters prompted me to drop a show, I understand why some of them chose to give up on the show when the specific thing that they were fans of went away (or will go away, in the case of the Ponds and Matt Smith). I'm just not convinced they're actually Doctor Who fans.
Lastly, I still don't understand what you're saying about the budget. To my way of thinking, quality and budget have very little to do with one another. A bigger budget may have made the Scribble Monster or the Dobby!Doctor look better, but "Fear Her" still would've been 10's weakest story, and the idea of being able to rejuvenate yourself by attuning yourself to the collective psychic energy of the planet would still be silly hand-waving. Conversely, a more realistic giant bug-thing wouldn't have made "Turn Left" better, except in the most superficial way. (See also the movies Jaws and Alien.) But I'll admit my opinion on this may be informed by having become a fan during its original run, when the effect were genuinely bad even by the low standards of the day.