Viability of Skills for the end game

Are certain skills not viable for the end game meaning that they perform poorly to the point that they are not worth pursuing in an end game build? For example, I can understand that RuneMaster and Runic Invocation builds are popular, but what about a skill such as Volcanic Orb? I’m very new to the game, but I come from D2/LoD and D3. A customizable Frost, Fire, or Lightning Orb sounds awesome. However, I don’t want to put 500 hours into a character and build and the skill isn’t viable. So are there skills that aren’t viable? If yes, then is it listed/documented somewhere? I plan to experiment for sure but I figured it would best to ask before I embark.