Personally, I'm happy they're going with Flashpoint for several reasons (and this is assuming it's a close adaptation to the original story):
1.- Seems like everyone and their grandmas wanted a smaller, simpler "origin story/first movie" with Barry vs the Rogues, but why really?? First of all, the movie itself could come across as "more of the same" when it comes to heroes first solo adventures (i.e: Antman, Dr Strange) - WW gets a pass for being a period piece and the more unique elements of the character - and that's not taking into account that the Rogues, unless they're banding together and in large numbers, wouldn't pose a real thread for someone as fast as the Flash (the tv show, as enjoyable as it might be, dumbs Barry down to a ridiculous level to get the Rogues to get the best of him, and the comics present no sense of dynamic perspective, so that's a whole different thing). Starting with Flashpoint from the gate is a very unique concept/move.
2.- It's big. No need to start small with it, but go all out; no need to have small adventures and then the "event movies"; why not make every movie an "event" (when it comes to the big powerful characters like Flash or GL, of course; street level heroes is another story).
3.- It presents the opportunity for some crazy visuals, storylines and alternative versions of characters which by that point (release date) will be a lot more familiar to audiences; again, the uniqueness of it.
4.- My main reason; all of Flashpoint's reason to be can be summed up as "Barry's one, big, idiotic mistake" (changing the past to save his mother ignoring the possible consequences); I much rather him making that idiotic mistake early in his career than later on, when he should know better.
Just my two cents.
Also, I'm willing to bet that there will be no "reboot" after this (and all the universe build-up that the movies leading to this are doing); the whole "reboot" talk is just wishful thinking from the people who are unhappy with how the DCEU has been going; they're doing minor adjustments to appeal to more of the mainstream audience (whom by the way, have made the first 4 DCEU movies insanely successful money-wise this far, so not that much hate there) and win over some detractors, but they're putting a lot of work, time and money into building this universe, they're not gonna throw it away, and they're specially not going to plan to throw it away while they're still producing other movies to lead to this one; if any actor leaves, they'll recast and act like nothing happened.
