What difficulty were you playing on? I run out of stamina quite frequently when facing a boxer with higher stats if I just throw as many punches as possible. Just yesterday I fought a boxer rated 92 against my middleweight who was rated 87. This guy had much more strength and toughness than I did, but I had slightly more speed. I made the mistake of throwing as many punches as I could, and by round 7 my stamina was almost completely gone. He knocked me out in round 8.
Maybe you can get away with that strategy on the easier difficulty settings. Doubt it will work on the higher settings. I can't comment on the multiplayer though. After looking at the ridiculous requirements to earn the L, XL, and XXL achievements/trophies...I vowed never to play the game online. I am not a fan of whoever thought up those frakkin trophies.
I was playing on "Pro," the game's default difficulty. Certainly my stamina would fall over the course of a fight, but it was easily replaced with the "points" you can assign between rounds. Definitely never ran into a problem of tiring to the point of being ineffective.
Online, I had opponents who would literally spam left and right body hooks over and over again. I could block them all I wanted but it didn't matter because the player hardly took a hit for stamina.
Initially I'd agree with alot of this review. The hidden gem i found was the customisable game sliders in the options menu, this allowed me to tailor the fighting experience to a much more 'realistic' style, more damaging punches combined with less stamina, aswell as tweaking CPU fighting habits helped turn the fights into a much more accurate boxing analogue than the rock-em-sock-em default settings.
I only discovered this after some browsing on the forums however and it's initially very confusing what the effect of each slider does and there are a few that i feel could be added (such as punch accuracy). Sliders however don't help the default online experience, which has moments of brilliance but is all too easy to ruin by the body punch spam you mention.
The only thing i disagree with is the Pre-round system. Particularly in multiplayer i found the fnr 3 system far too cumbersome and slow, it broke the flow of the fights too much for my liking. The fnr 4 system, whilst simplified to the extreme, does allow more streamlined and, most importantly, simultaneous play whilst still allowing some tactical depth.
Overall a pretty solid review (I still think FNR 4 is better overall however, even on default, lets not forget the parry system afterall :P)
Glad you've discovered the joy of ESPN's FNF: I've been watching regularly since 2000 and love Teddy's at-times-insane metaphors, some of the best unintentional comedy in broadcasting.
Also interesting to see that slider settings remain the saving grace of poor design the way they've been for at least a decade now (anyone remember Geocities pages with slider setting suggestions for PS1 games? That was pretty much my first experience with the Web.)