I dunno if I can concur about the "old" aspect of the pros at night. Was there on a Friday late night (within the last month) and there were at least a dozen prowlers under 30. Nice ones, too. For the oldies you gotta roll up in the alleys near Longshan Temple or the "barbershops" near Taipei Main. But suppose that's not what this is about.
I can concur about a vague revival of Combat Zone bars. Of course, Malibu West or whatever the fuck it's called is still kickin'. Further west down that lane (32) are a few places you want to avoid, like, stay the fuck away unless you got business there, i.e. Chatter's Pub, Farmhouse, My Place. Anyway, I was surprised to see B-52 was more or less jumpin' about a month back.
The Maji food court at Yuanshan has a few watering hole type joints. Loads of English-speaking up there.
It consistently confounds that there really isn't a bar scene in Tianmu. I've rationalized it in many ways. There is a cool lil funky joint within the Shilin Night Market - the owner (I believe) speaks fluent English.
Went into the Brass Monkey at Xinyi Warner the other night and was reminded why any BM establishment would never be on a personal list of bars to visit. You can smoke outside, that's a plus. The staff there really seems to care - about not giving a fuck. Otherwise, I can find the same sort of indifferent scorn standing outside any 7-Eleven.