Something I haven't seen directly mentioned: We keep talking about limited spells / abilities and bash EQ2 more than any other system. As someone who played EQ / EQ2 extensively from Beta, I hope consideration is made for the forward direction of the game. EQ2 on release wasn't anywhere near as spammy nor bloated. It actually had a mcuh quicker pace than EQ1, for sure, but it was bearable. What KILLED the game was every xpac and AA. More additional skills were introduced and very little of it was passive. Then you add in +spell haste / +reuse speed that compounded exponentially over the years and you are left with the state its in today.
EQ1, on the other hand, had some quite long spell casting times. 4 - 5 second wizard casts, etc. Even with powerful spell haste 3+ expansions later, it still allowed plenty of manageable time to pay attention to what was going on.
Short version: If you start with abilities taking 1-2 seconds to cast (end game), then quickly introduce methods of speeding that up via later xpacs, it snowballs quickly into spam combat. Keep this in mind from the start!!