I'll give you some technobabble: traffic shaping, ack-priorization, quality of service, traffic class.

All things which your home gateway should have in one form, or another, where you designate torrenting a priority which doesn't interfere with the rest of your activities. And adapting dynamically. No need to think about how to slice available bandwith into pieces beforehand.

Nice in theory, but as far as I've seen, most home routers and devices don't utilize those, and most users don't know how to configure them, and the up/down ratio is so vast (like mine is 1000/20, a 50x difference) that it's hard to saturate the down without first maxing the up in a torrent. The exception to that is it you happen to get some phat-piped seeds who are willing to send to you super fast even if you're uploading at a trickle. But in that case, plain old HTTP would've worked better anyway.

At the end of the day the bottleneck isn't at the protocol level, but the asymmetry of home cable connections. Torrents are great when you have symmetric fiber, but very few homes do right now.