Sunic -- you seem to think that this is a purely binary issue ... but it isn't.
There is a whole lot of middle ground between "totally laugh a any/all level-appropriate encounters" and "get regularly destroyed by level-appropriate encounters" ... you seem to be ignoring that fact.
Hi Welcome
No I'm not. The game is balanced around spells. As such, spells are the only things that can be considered mandatory. You take away the only means of dealing with encounters and you are left with no means of dealing with encounters.
Conversely, you make everything have spells and you have 4.fail.
Nah, if everything had spells 4.Fail would actually be interesting. Instead they made everyone like 3.5 Monks = minor, random, and inconsequential abilities.
By the way, if you DO have a 95% chance of success you have a 50% chance of dropping dead a level every level. So, who wants to play in a party where 2 levels from now only one original member is still alive? And remember, the ability to raise the dead is eight levels away, and costs a level each time. So you see, it's worse than that. It's not that you must have a 95% success rate to be not worthless. It's that if you have a 95% success rate you still are worthless because Iterative Probability annihilates you. Even a 99% success rate puts your half life at 5.2 levels - as in, 5.2 levels from now, there is a greater than 50/50 shot you have dropped dead at least once. Hint: There's 20 levels in the game. Even if your campaign does not cover all of them, you still must have a near perfect success rate on any given encounter in order to survive even a short campaign.
Is this seriously your perspective of DnD? Is this how you play or run games? I just need you to clarify because I doubt anyone on these boards runs their games like this. In fact I doubt you even run your games like this because there is no way that you expect an adventuring party to be able to handle a situation with a 99% success rate.
From the sounds of it you can't actually build worthwhile and meaningful encounters at all, so I don't know why you are even in this conversation.
Hi Welcome
What do you think "20% of resources" means? Hint: It's something like "This isn't meant to be a real threat at all, not even slightly, just use a little resources."
And it's called Iterative Probability, where you remember PCs only need to fail once, and therefore 95% success rate per encounter drops to 50% once you've fought enough encounters to gain a single level, and 99% success rate per encounter drops to below 50% 5.2 levels in. Therefore, anyone remotely serious about optimization must IP proof themselves by making their failure rate as low as it possibly can be, that way it doesn't approach 1 so quickly over the course of the campaign.
And you think I can't build good encounters? Bitch please. Why don't you go say that to someone that's actually played with me as the MC, hear the peals of laughter at your expense. Fact of the matter is even good encounters can be > 99%ed. It just requires IP proofing measures.
Here are a few examples:
Saves. Pass these on a 2 or better. It's not possible at low levels, but at mid levels it is doable and at high levels it is easy. Immunities are great too. Get as many as you can. No auto fail on a 1 + pass on a 2 or better can mostly substitute for an immunity. Watch the no saves though.
Real defenses. Get them. AC is not a real defense.
Anti full attacks. If it takes 2 to kill you, you're fine. If it only takes one, you have serious problems. Good fucking luck making it take more than 2. Things like Abrupt Jaunt, to avoid being full attacked in the first place are even better.
Init. Win init or die is a double edged sword. Do make sure you're the winner, as there are harsh consequences for losing Rocket Tag. And even with the previous measures to somewhat let yourself be able to withstand an attack, it's better not to risk it.
Good offense. Winning init alone is useless, you have to do something with that first strike. If you are a beatstick, you must be able to win the DPS race or you are worthless. Not to mention dead. If a caster, good save or loses, or lose or loses are the way to go.
There's plenty of other ways to IP proof yourself, and if it weren't for the fact you have already proven yourself to be an idiot I'd question why I have to explain basic optimization techniques to someone on an optimization board.