Book time. My opinion is pretty simple: they're not ban worthy at all.
I'll start with Seadra, in the beginning of 5U, it seemed incredibly strong. It was, and we had no idea how to play around it, or what works in the tier. Scrapping that thought is absolutely necessary, because it's not as strong as it used to be. I personally rank it at #3.
Most 5U teams have (at least) Seadra and a second water type, meaning Seadra is very easy to neutralize. If your opponent has his Seadra in, you usually send in your own, spam moves either to freeze or to damage it (Surf/Dedge) to force it to rest as quickly as possible. Doesn't this remind you of something ? It's the exact same thing that happens in 3U with Vaporeon and Dewgong, are they broken ? No. They work differently in 3U than Seadra in 5U of course, but I honestly think a sleeping 5U Seadra is useless, whereas sleeping VapGong have very high chances of waking up and being useful later on the game, for two reasons: better bulk, and the stuff that you use to pressure them is easier to switch into than the things you use to pressure Seadra in 5U. Once Seadra is asleep, you can pressure it with:
- Gastly, 40% chance to 2HKO
- Drowzee, 25% chance to 3HKO not accounting drops
- Dragonair, and man if that thing switches in it can either 3HKO or simply set up Agility, not sure you want to let it do
- Primeape, 3HKO
- Pidgeot, 3HKO
- It allows Poliwag and Kabutops to set up
So yea that is definitely punishable, but Dragonair is the main thing to account for even Gastly's everywhere. Also having Seadra + Seaking means opposite Seadra is completely neutred even in the case of a freeze, and if you have a Poliwag Seadra is one of the only switch-in (assuming you have Psychic which you should have) so you make it sleep quickly. I insist on the fact that sleeping Seadra isn't useful midgame because trying to wake it up can lead a loss of momentum, in a not very bulky tier. Imo Seadra is fine. You also spam Waters not only for Seadra, but for Ninetales and Magmar too. Kabutops can be very dangerous.
Now let's talk about Dragonair. It's indeed a very strong pokemon. The reason why I think it's not broken is quite simple lol: Gastly. The little ghost is pretty much the anti meta pokemon. It's so good you don't even use it ONLY for Dragonair. There's sort of a war between these three.
It's pretty much: Seadra is strong, Dragonair makes it not broken, and Gastly makes Dragonair not broken while being useful against Seadra. You just end up with a centralised metagame.
Wrap is boring to go against, Water vs Water can be boring to play, but it's not broken, therefore I think => No ban needed. In all the recent 5U games I played, none came down to wrap spam or freeze wars (small sample, let's see how new frontiers go)