The combining buff thing just sounds like a macro, unless you mean they actually all cast at once. I could imagine a high level spell taking twice as long to cast. But... it fires off 3 buffs. So it's worth the trade off if you can protect your priest from receiving any interrupts.
To go even further, this MMORPG called Ryzom (which ultimately failed because of competition) actually let players design their own spells.
While in Tyranny you get some limited spell creation, in Ryzom you could ajust every single parameter of a spell :
- area of effect
- cost (mana ? health ? both ? cast time ?)
Want a fireball imbued with paralysis ?
Here you go, it's either 3x as long to cast though, or you pay double the mana, or it has a much shorter range...
Want a heal which also hastes you ?
OK, double mana.
Want an AOE nuke which deals fire AND corrosive damage ?
Here you go, consumes some of your HP though.
Want to mana vampirize this pack of mobs ?
But of course, here spend some HP and cast it at a reduced range to offset its cost.
I for one have been waiting for years, for a new RPG to actually let me create my own spells however I want.
While Tyranny was OK-ish in that regard, it's still far from enough.
Dual casting wherein you can combine 2 spells to get their effects in a single cast, is porn for players.