Yeah, given access to the same gear, any two characters in the same class can become completely identical.
I'm ok with that. The designers said in D2 your stat choices often boiled down to:
- X amount of Strength for your end game gear
- Y amount of Dex for your target block
- 0 Energy
- everything else in Vitality.
And for talent trees, you could make your choices, but it was an enormous time sink to recreate a new char if you wanted another talent build. So interests of fun, they basically removed the barriers to respeccing.
With D3, there is an enormous variety in skill choises. Something like 24 skills, each with 5 rune variations, split over 6 slots. A lot of room for experimentation and differentiation. Even more when gear effects are added on over the top.