Some of the Githyanki have spells and they already have extra attack, so can they right now cast two spells in one term with their two actions?
If so that would indeed be a major problem for caster classes with extra attack (most notably valor bard), unless they decide not to give valor bards "extra action" but a different feature to prevent this abuse
If this is indeed an issue, I wonder why, since not just EA is getting developed and playtested, and that seems like one of the most obvious interactions to notice. I strongly hope we get level 5 soon, maybe even in this patch.
I really like the game, and could absolutely see it being a future classic, but honestly it seems like they need more time still. Some fundamental systems are still broken and unfinished (what worries me here is that it is not just stuff being held back, many of the old subclasses still have unfinished features (GOO warlock, the other pacts etc))
Honestly I would prefer it, if they took another year to make the game, though that probably is not possible with their monetary constraints