Stealth skills aren't a melee vs caster thing, they're a sneaky vs nonsneaky thing. A caster can potentially have high stealth; that's fairly popular in fact. If stealth and antistealth skills were buffed to the point of having PVP value, a PVP build would probably need to include them henceforth.
As for as sneaking up to someone and tripping him: You won't even get an attack roll, because you won't be within reach. Why would the enemy let you into reach? You can test it yourself: go into sneak mode, and then ask a helper to pretend he doesn't see you, and yet prevent you from reaching him. It's not hard.
Shall I suggest that females have a much larger amount of opportunities for football, due to the recognized imbalance?
You're suggesting that a weak opponent would be given more opportunities to fight, because the challengers think they can win. That may be true, but unless he enjoys losing, he'd tend to agree to many fewer fights. Assuming similar player psychological motivations, it evens out.
If you don't believe me, you could test this stuff. There are PVP rooms already in DDO; with a few other players to help, you should be able to see what actually happens.
Incorrect. Those other communities are based on game designs that are fundamentally functional.
No, I did not ignore them. The example made no sense, and was unrelated to "equal balance".
This looks like a basic logical error: Having observed that differences do not prohibit balance, you decide that differences are irrelevant to balance. That's unjustified. Here's the reality: Game balance is hard, and is unlikely to happen by accident. Simply having a bunch of characters with different strengths and weakness doesn't magically mean they'll be useful for different PVP needs in an entertaining way.
Do you know the difference between "is a goal" and "has been perfectly achieved"?
What, you're saying Diablo2 is as unbalanced as DDO? No. The fundamental core is more balanced, and even if there exist certain items that can be overpowered in combination, they're fairly restricted in natural and could be specifically disallowed by match agreements. Not so with things such as "divine spellcasting"
They're not different, which is shows the problem. The current restrictions created by some players are quite inadequate at producing entertaining PVP on a meaningful scale, and similar ones would be no better. And of course if there was an actual reward for victory that persisted outside the memories of people who viewed the fight, you could forget even about those kinds of limits being used.
If you want to PVP, then the primary consideration will be maximizing the percentage of other characters that you can defeat (possibly with an emphasis on other PVP-focused builds). As PVP consists of defeating other player characters in combat, the ability to defeat player characters will naturally be what is encouraged.
You've still got this idea that stealth is significant. It might help you to consider what would happen to a rogue who (somehow) sneaks up to a paladin or barbarian and thus gets two free unopposed attacks. What's he supposed to do next? (That's an experiment you can conduct with a helper)
I suspect if you elaborate on that suggestion, the shortcomings will become clear.