Imperial troopers in the arena are a sliding scale.
Five trooper Veers lead is not a good idea in the arena.
There are four, three, two, and one-trooper configurations that can work out quite well.
Personally, I run a Thrawn and four troopers configuration in the arena. It's a fun team, but I don't recommend it, but I'm kind of locked into it until I free up some resources from other commitments. And probably until I get JTR. For PvE, though, it's great, and on arena offense, it's a decent counter to nightmare, as Vader feeds the party a ton of turn meter with Force Crush.
A Krennic troopers lineup is as close as I'd recommend to a full trooper team as I'd recommend, and even that's fairly dated. Krennic, Deathtrooper, Shoretrooper, zVeers, and either Thrawn or Starck. Preferably Thrawn, as his interaction with Krennic's leader ability is hilarious.
Veers' leader ability, unfortunately, isn't great. And Empire has a lot of great leader abilities. His unique is more important to empower troopers, so unless you're forced into Veers lead, like for the IPD fight, it's usually best to use a different Empire lead.