I don't like splat zones because it totally flattens the otherwise deep and nuanced gameplay and balance.
The scope of pressure and control is severely reduced, because you are either running the clock down or you aren't. That factor is so important that it totally minimizes the affect of zoning and reducing opponents options. Basically you're either winning or not. There's much less give and take.
This serves to greatly minimize weapons options as well, especially (it seems, I haven't played in a long time until now), with the increased range on snipers. It's so easy to camp a splatzone with a sniper rifle, and the splatzone is the only place on the map that really matters, so range and DPS are over-emphasized. As a squelcher user, this really sucks. This is an oversimplification, but it's basically get a charge weapon or roller, or GTFO.
Some maps are worse than others. The campground one is actually pretty fun (in fact, splatzones is better on this map than rainmaker IMO), but museum, port mackerel, and hammerhead bridge are such basic carnage pits that it makes me just turn my console off or play something else.
I dunno, just my opinion, probably greatly influenced by someone that plays with squelchers.
EDIT: I will say that I greatly prefer splatzones with > 1 zone. Then there's the possibility of longer stalemates and more strategic decisions around which channels to attack, and which areas to prioritize or provide backup in. With one splatzone though, it's always all-hands-on-deck for the splatzone, or maybe spawn camping.
