I generally like to have the Cruiser 1v1 proving ground back.
In the assembly hall I made a post on how this could be done without the pve part: Burner proving grounds as a replacement for the old 1v1 arena at the end of abyssal sites
The idea is that you always get in and have the 5 min timer on the cache as on the old arena. But instead of leaderboards and format restriction, you get better loot from the cache the higher the chance is that someone shows up within the 5 minute timer. And you can bring any Cruiser, you could bring a cheap T1 Cruiser or a 5b Ikitursa just like the old arena