One thing to, perhaps, bare in mind when making comparisons with Ichigo, is that Ichigo is not an even-keel. His ability and power fluctuate to what seems to me to be an order of magnitude or two. Case in point, I think of the Ichigo/Byakuya and the Ichigo/Kenpachi fights. There was only one point before the hollow took over that Ichigo dominated the fight, and that was at the first moment of of his bankai and he put the tip of his sword to Byakuya's neck. The second time Ichigo tried that, Byakuya caught Ichigo's sword in his hand. Sure, he was cut, but why didn't Ichigo's sword reach it's mark? (I'm pretty sure he wasn't aiming for Byakuya's hand) I speculate that it's because Byakuya isn't a complete wanker. Ichigo then slowed, stumbled, had a kido through the chest and a sword in the foot. He's a gonner at that point. Without the hollow to pump some life and engery back into him, Bleach would have been a short, Seinen anime, ending the death of Rukia and everybody else, having a subtext of the fulitility of exisitance. Now, consider the Kenpachi fight. Without his hollow...at least indirectly, as he made a show in the inner world...Ichigo is able to defeat, so to speak, Kenpachi. Now, Ichigo is suposed to be much more powerful now. But he was easily defeted, injured though he was, by Nnoitra...even Tesla, the arrancar form Renji...gave Ichigo the smack-down. Nnoitra was tough enough to force Kenpachi to use a little technique. And when Kenpachi used a two-handed technique, he took out a fully released Nnoitra with a single hit. Now, Ichigo defeted both Byakuya and Kenpachi. However, does he win against them 10 times out of 10? I think not, because he is not maxed out 10 times out of 10. Remember too, Ichigo got o(p)wned by that Bount dude who was in turn o(p)wned by Toshiro, often speculated as the weakest of the captains.
So, I take with a gain of salt any argument along the lines of _______ is tougher than Ichigo who is tougher than _______, so thereful _______ is tougher than _______.