A good map is a small map. You shouldn't have to walk far to get to the action.
Your map is the smallest push map I've ever seen, that is not necessarily a good thing as heavy will be way too viable on the map. Generally speaking, if heavy is too good on a map, people will not like it, this is speaking mostly from 6s but it can apply to pubs too. Most people don't like to have to focus a heavy, and that's the only way to deal with a 450 hp turret. Comp banned the GRU and the Steak Sandwich because they didn't want to deal with a pocket heavy, heavy is boring to play and it's boring to fight against. The major fault against Gully is that a heavy is way too viable on the map, and it's the smallest map played in comp that I know of. Idk, I don't see your map really being played outside of insta spawn servers unless you make it larger, but I could very well be too drunk to think reasonably as I've been drinking most of the night
That's my opinion, do with it what you will, it is your map, after all