McCoy was "my" childhood Doctor too, so will always be fondly remembered. But I've not dipped back into those episodes since, so goodness knows how they would hold up now.
I have watched some classic episodes/arcs from time to time, and I have a vague plan to watch all the "critical" episodes (e.g. all the ones concerning Daleks, Cybermen, Master, Timelords/regeneration) but there are so many missing episodes, and the ones that are on DVD are a bit pricey for my tastes.
The modern Who is geared to the modern audience and I am a big fan, mostly. Ecclestone was a great choice to revive the show, Tennant was a very strong choice too. Smith took some getting used to, but he had a great energy and I was 100% on board with him as the Doctor before long. Likewise with Capaldi, he's very different but still "the Doctor" shines through..
The older format of 4-6 week arcs of 20 minute episodes wouldn't work these days - the ones I've seen have plenty of padding in the middle episodes too. But the modern show definitely has too mush running around, and too many "end of the world/universe" plotlines. More intimate plots, well executed, tend to yield more emotional results. This week's show (Listen) being a good example of one where the "threat" wasn't about to bring forth the apocalypse yet the story was engaging.