Depends your flavour. Bruno is 0.5 more expensive than Trent. 2 years ago he was 12.0. Arsenal mids are 0.5 more expensive than Trent, Martinelli on par for price. Last year they are 200 point players too. Arsenal have much better fixtures than Pool. The "experts" will say don't take Martinelli because of rotation, but his 70mins could reap rewards anyway.
It all comes down to each individuals interpretation. Quoting last years numbers is all well and good for both of us, but prices from last year have changed. Trent has gone up. Arsenal has gone up. Bruno has come down. It's not as simple as Bruno vs Trent, it's also taking Mitoma types too which is relative to the argument. GW4 rolls around and I'm not sure I want any Brighton. Europe starts and the fixtures turn.
I'm not anti Trent by any stretch. You can't rotate Trent. You can rotate mids because there are options.
Arsenal do have better fixtures than Pool, hence why I have 1 Pool and 3 Gunners. Let's not forget that Pool is a great side, and regardless of who they play, they can score well. They belted United 7-0. Trent offers a CS and/or attacking returns, is a nailed starter, so is the best risk and value hedge to ensure a slice of the cake should Pool get good returns.
Martinelli is quality, but based on last season, when everyone was fit, he made way. Jesus is probably equal with him, but takes up a FOR spot where there's not many other better options. Same good be said with Gabriel. He takes up a DEF spot. Martinelli takes up a precious MID spot, and is the only reason why he gets squeezed out. Relative to other ARS players and MIDs, he's not top 3 or top 5 in those categories.
100% we can't compare Bruno and Trent, as they're different positions. Bruno suffered when Ronaldo came back to United. Pre and post Ronaldo, he's done well. After the WC, he got something like 25 goal involvements. Given United didn't get too many PKs, that's probably his base. As you eluded to, his current price of 8.5 is well below his historic price, so even if he plays deeper, he will still be value, but now has huge upside.
For me, it's Rashy vs Bruno of that MID spot. Rashy also had an extraordinary year by his standards. He could go back to being MIA or injury prone. I think I'll probably end up going Bruno in the end. He'll do better than Rashy and give you an extra 0.5, which will come in handy when we need to go Trippier and Botman over 2 x 5.0 DEF in GW5-6.