I don't like RTS games but I love every other game Larian made so I played Dragon Commander and enjoyed myself.
If they don't implement reagents will you still play? I'm assuming a yes answer here. Will you limit your use of certain skills because you think they are OP? If you do then you are following my suggestion. If you feel it's too easy why not challenge yourself? I've played plenty of games where I felt it was too easy so I decided to not use X skill or only hit because it would make it harder. My suggestion is for if they don't give lower cool downs then just refrain from using it for a few turns.
And yes I know they drew a lot of inspiration from Ultima. Doesn't mean I won't like this game, and so far I do. For all we know the most powerful skill could take five turns to cast and if you waited that long you would probably be dead. To be honest I forgot they were adding a cast time till you reminded me. Which in itself could solve a lot of problems.
We both have strong opinions and I for one am not saying you're wrong. But that a better solution might be available. I think we can both agree to disagree on the subject of reagents. Let's see if the cast time helps before we try. to think of new things to change