I dont think HTC need to close one arena just to open another. I mean, they can add more arenas w/o closing existing ones.
Anyway, neither "fighter arena" nor arena with fighter's town would change anything, exept for 1-2 first weeks maybe. Most of ppl dont want to play in near empty arena, most of ppl dont want pure dogfight as well. Time ago there was "fighter arena" as Combat Theatre setup (more than once, afair), it hasnt any success on big scale.
btw, ppl who want pure dogfight can do it in DA or TA right now, they dont need whole arena for it, just 3 fields close to each other.
Speaking about EW/MW arenas, a want them out of scoring system. Or give them separate score like CT have.