billd91
Not your screen monkey (he/him) 🇺🇦🇵🇸🏳️⚧️
What Balesir said: this whole thief vs wizard thing isn't a complaint that thieves can do things that other PCs can't - it's a complaint that there is nothing a thief can do that other PCs (particularly Flying, Invisible, Knocking wizards) can't also do.
Those who are attacking the UMD skill, and the Knock and Invisibility spells, are defending differentiation. Those who are defending that skill and those spells are defending homogeneity and thieves being overshadowed by magic-users.
There is, however, a problem with niche protection and maintaining abilities that no other class can do - the class risks becoming required. I want various degrees of overlap so that my players can choose to play a different mix of character classes and types without always having to play the big 4. I want abilities to be duplicated by magic items and other pieces of equipment to facilitate that as necessary.