Having realized the massive benefit of racing in a legally spaced pack, it makes me desperately want a longer draft zone. In Cozumel, I only ended up riding 250w avg, but had nearly my fastest bike split ever. I wanted to ride harder, but with the winds, I knew that if I tried to break away from my small pack of 4, I wouldn't be able to drop them and I'd just end up doing all the work off the front for no benefit. Instead I sat in the pack, leading as little as possible except for two surges. Boring. At one point I did glance over my shoulder a few times to see someone sitting maybe 4 meters behind me, prompting me to sit up, give them the finger, and yell some not so nice things. He dropped back but it pissed me off. Saw him blatantly drafting off Taylor Reid right in front of me when our pack first caught him.
In addition, I would assume the drafting benefit does not scale linearly on distance. If someone cheats the distance to say 8 meters, right now they may not get a penalty because that's close enough, but they're also getting a much bigger benefit than the legal 10 meters. If the legal zone was 20 meters, if someone cheated up a bit to 16, they're benefit is much smaller.
So I guess the relevant part to your question is, does having the legal distance short enough that there is a benefit make racing more interesting? It certainly makes it more tactical but from a being in the race perspective that's kind of disappointing. Despite the potential benefits of drafting on the swim, triathlon is arguably an individual sport we do at the same time as others. I'd argue the mental aspect of being out there with others is tactical enough and we don't need to add in physical advantages to be gained as well.
20m draft zone would be great, but you could only do it for pro's. There are so many AG's normally that it can be tough to keep to the current draft rules. It's not realistic to have 2000 athletes all 20+ plus meters apart. If it was done for pro's only, BOP pro's ans FOP AG's mixing could cause a bit of confusion!
Pretty sure Challenge races have 20m draft rule for AGers as well