Hard to say. If we assume Kaido is the strongest being currently (which is fair), then I'd give it to Kaido since I don't see Prime Rayleigh being much stronger than Shanks if at all.
I think he could be. We still know nothing about Shanks, he's pretty well 100% hype at this point. His best feats are clashing with Old Whitebeard and Akainu. It's quite possible that Mihawk is stronger than him as well. Perhaps he's been slightly overrated by the fan base, or perhaps not.
I think he's around the other Yonko in power, but I wouldn't be surprised if he was the weakest of the bunch by a very small margin. Mihawk's Vivre Card makes it sound as though he is stronger than Shanks at this moment, and if we consider Kaido to be the strongest in the verse, Shanks would have to be a bit weaker. I'm talking very slim margins here:
Prime Rayleigh: 90-95
Kaido: 90
Big Mom: 89
Mihawk: 89
Shanks: 88
I just don't agree with Rayleigh beating Shanks let alone the strongest Yonko. It just seems off to me. I'm ok with them being equals though. It might be easier to swallow for you since you tend to have Roger stronger than the Yonko by a substantial amount.
That's part of it, yes. I do think the past generation was stronger, which is part of the reason why there are Yonko now instead of someone breaking out of the group and becoming the pirate king. Rayleigh is definitely a question mark but I feel he's deserving of the hype after what Garp said about him. This is how I see the top tiers:
Roger: 100
Prime WB: 100
Shiki: 97
Prime Garp: 95
Prime Rayleigh: 90-95
Kaido: 90
Big Mom: 89
Mohawk: 89
Shanks: 88
Not sure where Old WB fits in among the group. He's said to be the world's strongest man but can't use Kenbunshoku or Haoshoku???
You can't deny that it fits like a puzzle and also it's hard to see Mihawk being the strongest person working for the World Government. There has to be SOMEONE that could best him in a fight in case he needs to be taken under control.
They have 3 Admirals though. It's hard to imagine a situation where Mihawk would go rogue and there wouldn't be more than 1 admiral available. Also that would make it very questionable for Blackbeard to accept Kuzan into his crew when he was equal to Akainu. Blackbeard was without a doubt the weakest of the Yonko and probably still is. That wouldn't make much sense to allow someone who could decimate his crew to join them.
Well I think he's set to fight Dragon in the future and have a feeling he's going to win that fight. That's just me though. I don't think he necessarily has to be 2nd strongest or whatever but I think he's like top 5.