Can't say Wilde for definite because his record is all you can go off really. There isn't enough footage unfortunately and you can't make a judgement on how good the fighters he knocked out actually are.
It is almost totally an abstract concept. We are being asked to compare 90lbs men from the 1880s to 300lbs men in 2014 and every boxer inbetween. We are then being asked to calculate some kind of measurement that can accurately predict the potential power of every said fighter and ranked them. Thus I think lack of footage is hardly a major knock in this judgement. But the stats are there, it is generally considered Wilde stopped more fighters than any other known British boxer. He also is well known for giving away as much as a fifth of his body weight, in catchweight contests with world ranked fighters.
A lot of people saying Benn, he certainly could bang but I don't think he hit harder than Froch, and I am not saying p4p Froch is hardest hitting. what I would say could any SMW in world go toe to toe for 12 rounds and trade continually with Froch? I would say no, some did with Benn
Froch hits hard, but his skill is in having a chin seemingly made of metal. Don't think he hits harder than Benn personally.
Boxers that I've witnessed in order of power p4p: Nas Haye Lennox Benn Lennox was a big man so naturally had a lot of power. Benn was a decent sized middle that carried his power over to super middle. But pound for pound its Nas, who carried KO power in both hands and Haye, who carried his KO power over from Cruiser to HW. Haye isn't the biggest HW but could KO most HWs out there.
Eubank could punch when he threw properly and landed well. I remember Johnny Melfah standing up to everything Benn swung at him in the ABA final - Eubank got hold of Melfah and one single short right hand completely flattened him and completely shattered his jaw.
Eubank could punch when he wanted to. As for benn vs froch i think benn was a bigger puncher with single shots but froch relies more on culmative and swarming