1) Christos Gage... he'd never watched Buffy or Angel before being offered the job, then found himself addicted once he started watching. I honestly think an outsider's perspective was sorely needed, especially since he got the characters better than the other, more entrenched writers.
2) While I wasn't a big fan of the Spike miniseries, I don't think it's Victor Gischler's fault. What he did have control of (meaning the actual words of the writing) wasn't a problem, the problem was that the story only existed to change Spike's status quo, not because it was an interesting story to tell in itself.
As for how Angel & Faith ... I said, I have faith in the writers
Well, let me tell you this much, I did the same thing with Gischler that I did before start of S9 with Gage - I read his other works in order to see what to expect - even tentatively.
I want to say that my estimate of CG was a bit off - I expected much less of him. On other hand, now in retrospect I can see what I missed and what proved to be his 'style' of storytelling.
Firstly, CG tries his best to write complex villains with complex, sometimes murky and esoteric ( not clear-cut) motivations. Secondly, he has personal fixation on the macabre side of the story. Expect lots of truly ghoulish stuff from him, edging on yer classic horrors, with a lots and lots of blood, gore, viscera and psycho horror. On other hand, he is rather shy when it comes to writing any sexual situation at all, and prefers to hint at the stuff happening off screen. CG is also - unfortunately - not very good at getting into the heads of his female characters. He writes a lot of them , but they turn out to be sort of flat. He had Rebekah though fleshing out the visuals, and she has a streak of romantic exaggeration in her art, liking to draw all things very pretty, male character super-masculine , female characters a bit overdressed and over endowed with flowing hair etc - but she does it on the romantic side of it, so it stays borderline tasteful. Her horrors are less horrific because of it, but it is still very good visualization of all things fantastic.
I have no idea what A&F artist is going to be all about, but I suspect they are not going to be anywhere close on pair with Rebekah.
Gischler, on other hand has a tendency to overdo gratuitous sex in his works. The sheer volume of voluptuous (naked or semi-naked) female flesh in his fantasy series is bordering on the side of teen male gratification. There is a lot of graphic sex depictions, a lot of f-bombing, and some of it (if not most of it) is utterly pointless plot-wise. To put it blunt, VG likes to write scenes featuring naked females engaged in sex a bit too much. (I remind you of his inserting Pearl shagging an insect demon in Spike mini, then having a succubus with bra size D as a supporting character - that was not an accident, it is his style.) His stronger side, on the other hand, is very dynamic fighting scenes, overall well handled multi-line-ed plot, with many secondary characters branching out of the main story plot done reasonably well. Gischlers rogue characters are usually a pleasure to read - they are funny and believable. His villains though are flat out mustache twirlers, and no quirky side or a fascination with macabre like Gage. His heroes, well, they are a bit on the boring side, but it is all very straightforward hero-ing, with clear cut motivations. (My predictions for Faith in VG's book though is that she is going to be very straight-laced , since she is a 'hero'.)
Personally, I will have a look at Gischler's second issue ( first issue will likely be heavily corrected by Gage) and then decide whether to continue A&F S10 of ignore it completely.