I have a few suggestions:
1.) There should be a way to cancel units in the training queue. You could be training units and, while raiding, realize you've expended a certain unit more quickly than you anticipated. Now you want to replenish that unit type but your queue is full of units you might not necessarily prioritize anymore.
Our devs are considering this idea.
2.) I definitely think the cost of reviving units needs to be looked at, or maybe implement a new currency you could earn to do so besides sapphires
Declined. We are not planning to make any changes to Infirmary mechanics.
3.) It would be handy to make a feature that allows you to rearrange your castle layout. When first starting the game, I was more concerned with learning what I was doing. I didn't realize you could select a different space for buildings until later because that arrow seems like it's telling you were to put those buildings in the tutorial. You could maybe make an item that you use (similar to the castle relocation items to move to different places on the map) to rearrange your buildings.
Declined. It's a good idea, but it's really hard to implement. It would require a lot of time and resources to develop. Maybe our devs will come back to this idea some day, but not in the near future.