Same thing happened to WB and he was still WSM so I think that doesn't matter. Hell, Garp, Sengoku and Rayleigh didn't have any heart problem nor did they need medical device sticking on them. So for all we know Garp and Sengoku were World's 2nd and 3rd strongest man hahaha.
Funny thing is in recent SBS Oda revealed that Garp, Sengoku, Roger and Rayleigh are all older than WB (I think about 3-5 years). I guess WB must have had it rougher looking after his sons LOL
Garp has the best strength feat in this entire manga (when he threw that gigantic iron cannonball at the Thousand Sunny. Better feat than Jozu's throwing iceberg or Hajrudin punching 10000 tons Machvise). His punch (and CoA) is good enough to leave a scratch mark on Marco's face despite the latter's being in full phoenix form (which means his regenerative power was working), something none of the Admirals did, even with their trademark attacks (at least on-screen. We know Marco got other scratches in the war).
Sengoku has that awesome shockwave that pushed back the whole BB pirates and later he and Garp took on all of them, including BB whose 2 DFs are strong as fuck.
Not much to go on compared to other characters who got plenty of fights, admittedly, but feat-wise and hype-wise still enough to put them among the strongest (2 years ago, that is).
Actually, we have only seen Marco can regen from physical damage (as in being punched, shot etc.) but I'm not sure that means he can regenerate from poison.
As for Jozu, he never turn full diamond and would still suffer from poison gas and stuffs.
We don't know the situation. Might have been a gang-up.
Wb is unlike sengoku, 1 he still had a concrete title there was no arguing his power. 2nd he had a much more OP df and fighting style that old age would damage less.
Aure his physical endrance probably took a hit, maybe his coo did too, and his strength without a doubt did. But he was still the user of the quake fruit. He still had his sword. He may not punch as strong as he used to or dodge attacks like he used to, but his quake attacks were as strong as they ever were. And that is something garp and sengoku dont have going for them.
I doubt garp's iron mase feat is better then saul's or oz jr's feat of throwing a battle ship, and those character's arent even strong. Neither of us know what that mace was made of entirely but if it was actually as heavy as you think it is then the battle ship wouldnt of supported it.
Ya WB's df has long range abilities, wheres BB and the others dont. Magellan tries to get close to wb with his hydra or even his super poison WB blows him away with a quake.
Maybe marco cant heal from poison but as of now i doubt it. I dont see the difference between internal damage of poison and the internal damage of Kizaru's laser blasting a hole in his head.
As for jozu he is fast, it took magellan some time to use his poison gas and he never used it on the move, jozu couod surely control the fight enough to get around magellan's slow gas attacks. I know we havent seen a full body dimond but i dont see why he wouldnt have it.
Probably was a gang up, wb would have the same gang up abilities. Only real differnece is WB has the ability to destroy ID wheres BB didnt.