ENDGAME MANA FLASKS WORTHLESS

at T3 a Mana flask only giving 400+ mana on RECOVERY is EXTREMELY LOW! i have over 2k mana that is not enough even with mana recovery jewels, mana regeneration. Mana flasks are useless in mapping and only useful for BOSSING depending on build mine isnt HUGE on DPS so i need to spam a couple skills to deal and doing this mana recovery is very slow- not too many mana on hit options- leech is not even noticeable IMO the only big MANA mod is GAINED ON KILL for map clear