The problem is that increasing the death penalty doesn't necessarily make a game more exciting. Since no one wants to loose months of effort, players simply compensate for the increased penalty by becomming much more risk-adverse. In a games like guild wars and WOW, most combat revolves around fair matches between relatively equal opponents. You might loose, but it's no big deal - you can just queue up for another match.
In Eve, fair combat is almost unheard-of - very few players are willing to risk losses when the odds are only 50/50. Aside from a few wow-esque exceptions (gangs of so-called nano-ships that move so quickly, they can easily escape when the tide of battle turns against them), combat in Eve revolves around two main mechanisms:
1) Gangs of PvP-fitted ships hunting down PvE-fitted ships, which have little chance of fighting back
2) Massive 'blobs' of dozens or even hundreds of ships whose overwhelming numbers reduce the likelihood of combat losses.
When you're sitting on a stargate with 50 friends, waiting to gank the unsuspecting player who jumps through, the penalty for failure is just as high as ever, but the risk of failure is quite low - so low, in fact, that it could be argued this form of combat is actually LESS exciting. Most of the fun comes from your ability to inflict serious losses on your target - wiping out weeks, months, or in the case of exhorbiant 'faction' ships, even years' worth of his playtime.
This is why, in general, low-penalty games tend to attract competition-oriented players who enjoy the process of competition itself, while high-penalty games attract grief-oriented players who enjoy the process of inflicting loss on other players. It should be no surprise that the largest alliance in Eve - Goonswarm - is an alliance of somethingawful members - the same 'goons' infamous for their large-scale griefing campaigns in Second Life and other games.