Is this the norm or the exception in dota?
More the norm rather than the exception. Each type of hero iusually has 2 or 3 build routes. By type I mean:
Ranged Int
Ranged Dex
Melee Dex
Melee Str
and there are a few heroes that are Melee int, and ranged str.
For each of those types, there are good item paths. For example, a Ranged Int could go disables/int items. This captilizases on their spell casting abilities. However, depending on their base skills, they could focus on damage only items and build a "battle mage" relying on their base intelligence score to be sufficient for the spells to suplement their damage. . Items builds for 1 melee strength guy are usually going to be well suited for another Melee Str hero.
Dwarven sniper is a ranged dex. As indicated, he can go all damage, selecting headshot, ranged, build dex/damage/attack speed items. This makes him really good to kill single targets fast with his ult (similar to Regulus's snipe) to finish off the target. Or he can get some mana and mana regen items, spam his ranged AOE spell and push down wave after wave of creeps. Its a trade off. Some people will focus on making him stealthy giving him a wind walk (temporary invisibility), and picking hiding spots in the woods to initiate attacks.
Many of the heroes in Dota have 2 or 3 paths they can take. The paths usually merge back when the hero gets to level 25 (all skills are maxed) and they have had time to invest in the core items.
Now, for Demigod, we don't really have the same classifications as DOTA. First, there will only be 8 Demigods. The 3 available Demi's can be sorted as melee tank, ranged DPS, and Ranged Caster. We'll see a melee DPS (unclean beast), and a few generals. It will be interesting to see how they all interact and whether they have singificantly different "builds" as indicated by the developers. I'd love it if each Demigod has 2 to 4 viable roles/builds they can work towards, each one having a significant impact on the overall strategy of the light and dark teams. Not only that, but that the 2 to 4 builds per demigod are fairly unique from those of other demigods.... Thats a tall order.