When you are battling 2 or more of the same character who produce countdown tiles. When you stun or make them airborne, could their owned tiles be greyed out or changed in some way? Maybe they all stay the same to force you to track them on a turn by turn basis. But, it would be nice for those who play at higher tempos to be able to see the effected tiles and target other enemies accordingly.
I still believe there should be a better indication of who a CD belongs to. The whole ‘cycle for a short highlight’ is way too subtle, and even veteran players sometimes don’t know about it.
I also like the op’s idea, a visual clue to indicate an ‘on hold’ status woukd be an improvement too, be it be greying out or maybe by a ‘paused’ outline behind the counter.
Actually, reading this back I just realized it could be similar to the ‘repeater tile’ styling, that features a ‘refresh arrows’ symbol. I’m sure a graphical designer could come up with something good looking.