I'd say as much as you can practice drafting, you can practice building sealed pools similarly(if not quite the same). You mayI much prefer Draft to Sealed. If you end up with a shitty card pool in Draft (or, shitty-er than the average card pool at your table, anyway) then that's something you can work on and improve in the future. If you end up with a shitty card pool in Sealed - oh well - it's not like you can practice opening better packs.
In every other format everyone either starts with the exact same pool of cards to make their decks from or you have some say in what your pool of cards looks like - in Sealed it's completely luck-based.
A crap shoot.
That's why I say fuck it and plan on just taking a guild I'm comfortable with.
not have say in what your pool looks like in sealed, but you do in your decklist and even then if you register garbage, you can often figure it out and board into the deck you didn't decide to play which you here pro players commenting on at every limited GP.
I concede that sealed is strictly speaking more luck based since in draft you are making more choices, but I think it's a myth that draft is the skilled format and sealed is all luck. I think on a sliding scale of luck involved from 1 to 10, 1 being chess and 10 being Russian roulette, people put draft at a 2 and sealed at an 8 when it's more of 4 and 5 respectively(or something like that, the numbers are made up).