I mean sure, but this just adds said bloat for no real gain over simply adding the second charge? The charge angle is just so much more elegant IMO.
I get the feeling you're approaching it from the angle that the WHM is going to be bottomed out on MP by the time that the 3rd Assize rolls round? That's not really going to be the case in any reasonable situation. Either that or your misunderstanding the main benefit in that the cooldown will keep ticking down whilst you sit on 1 of the 2 charges.
Rather the beauty is that right now, if Assize isn't on cooldown, as you say, you're leaving DPS and MP on the table.
With 2 charges, you can have assize ready to cast but still have the second charge ticking round off cooldown. So in your example, you blow both charges in the opener. Let's say the fight has a big raid wide AoE 1 minute into the fight. 2 charges will allow you to stall your next assize for the extra 15 seconds potentially allowing you to keep Asylum in your pocket for the next raid wide.
Remember that the entire point of 2 charges is that you don't have to blow the first charge on cooldown. That timer will still be ticking round for the second charge whilst you have the 1st banked for up to 45 seconds. On a fight like E12S this would be a huge boon for WHM IMHO.
The emphasis here is that until you are either flatlined on MP or the fight is about to end, there's no penalty for sitting on 1 charge and stalling it to align with either adds or some healing requirement. There's no need to keep both charges on CD right from your opener. If anything, doing that would be counter productive if you want to try and get 2 casts in with subsequent raid buff windows.
*edit* Holy moly that post reads badly sorry
