I look forward to them! We don't have very many cities that can build them though.
But for Corta Cana, Angola, Vai Você and Bananeira they'll be excellent. Lavandeira and Camunjerê can also build them, although in Lavandeira we're mostly working off river tiles because the rivers are all cottaged. Lone of the astro island cities as well - arguably I made an error there not planning for levees while dotmapping.
Wellerman would also look gorgeous with a levee, but given the activity in Charriu's thread I expect our musketeers to be mostly killed and us evacuating next turn
. On that note, I clearly don't have the nerves currently to play this game competitively. I'm having fun either way, but If civac declared it is possible I would just fold in a couple of turns due to trying something stupid...
Back to levees, we've been lagging in Mfg for a long while now, and I hope they'll help fixing that, together with US in the upcoming GA.
Regarding the cost, I think most people here would build a 60h monastery for the AP bonus, right? That's a building that obsoletes. Probably an 80h temple as well. So you could argue the levee should surely be worth it if you're working some 5-6 river tiles constantly.