I will frequently release a very quick blaze off of some of the above types of attacks. basically adding a nice chunk of damage for almost 0 mp. If Someone is readying a magnum or flame burst, I can easily get into position and get at least a medium charge going. This is all assuming mindless noob randoms.
One of the problems I have with Blaze is that I can't do quick shots. I used to be able to do it on my old laptop but once I downgraded to the one I use now I have to have it charged for at least half a second or else it will never connect. I don't know how in the world that makes sense but it's just one of the many problems I've started having since the downgrade.
So in other words, Blaze can be really inconvenient if you lag.
Usually I don't go for quick shots anyways. I only really pull out Blaze on the tough mobs with very high HP or def/prot, so I'm usually aiming to deal huge damage. As for setups, it really depends on the group composition, but usually its either Person A can't properly do a setup (either they don't know how, or they can't aim well) or Person B ruins the setup (ie Smash/Windmill/Range in the wrong direction just before Person A gets the hit in).
You'd really have to assess the people you run with and see if they're competent at party play before deciding whether or not Blaze will be useful to you. It's possible that you can mesh well with your group, but if you think (like so many non-Blazers do) that you can just run in and let loose unholy explosions on any enemy at whim, you'll be disappointed.