I would want his feedback on the construction of the running track, being the end user and all.
Beta Testing?
Ok, so 1 single aspect of an entire stadium maybe… wouldn’t be as keen for his feedback if he was a bit of a tosser tho 
From what i gather the consensus would be:
give the beta to people that will be devoted to do something about it.
And those are mostly regular forumees, modders&mappers and ‘key community figures’.
There is really an aim-assist? Lolilol!
As for the beta testing thing, its allways cool to try the game and spot the main bugs before it gets out, but I think its rather difficult to choose “good” ppl for this job, I think as stealth6 that modders/mappers should have the priority here.
Most of newbz cant spot any bugs and most of comp players are full of BS cuz the game isnt exactly like the game they played before and they’ll allways whine no matter what you do…
Experienced gamers is a bad term to me, I played game since 1990 including many fps as the doom series/quake series/ut series some cod, battlefield, CS, half life, sof2 etc etc… and I’m still a total newb at spotting bugs… Thats why I think its hard to choose who can access to the beta and who cant…
In final, give the beta to the modders/mappers accustomed with the engine and trust me they’ll find where the bugs are, balance issue can really be solved in later patch, the main point is to LISTEN to the customers and release quick patch if the balance is really broke, that way you wont loose ppl who will think game is shit after 2 week of playing…
Peace
I think looking for bugs and ironing out any engine issues should be the task for someone who is a little bit more qualified than the average gamer of 10+ years. However issues involved with balancing, an outside perspective could be pretty valuable here.
I remember the Sewer Beta for ETQW, where everyone raged, that each stroyent cell gave players a new grenade. It turned the indoor sections of the map into a complete spamfest, however this was eventually taken out.
Unfortunately some people have a low threshold for things like that and dont end up buying the game. Therefore a selective closed beta would be far better imo.