If you’re playing on area ruins it opens up a lot of strategies which are ridiculous and anti-fun. For example, you can move block with 32mm bases exerting a 5” diameter circle of engagement range to completely lock a unit with 6” movement in combat, even with desperate breakout.

In 8th Ed, 'desperate breakout' didn't exist. I don't recall players demanding tournaments to disallow tripointing. Preventing fallback exists in 40k in multiple mechanical ways, I don't consider this 'unfun'.

The GW open board also lets you prevent large bases from crossing the midfield by tucking models in the ruin corners to force a charge to get through.
Then charge and get on with it.

And as a GSC and BA player, I can tell you that while I love 7” charges out of deep strike, they aren’t healthy for the game. Every 9th melee codex has been written to avoid the level of uninteractive bullshit we saw in parts of 8th, and this brings it right back.

GSC are one of the least impactful 8th Ed books, and the prior long-suffering BA tend to start their stuff on the board anyway.
Charges out of deepstrike have long been a weak archtype to rely on. It's not unhealthy to reduce their required roll by 1 across the board *in some circumstances".