A foreword about me: I played a lot of DotA back when it was called DotA 3.3 as a WarCraft 3 non-expansion custom map. I played succeeding versions up to 3.7, Danite's Hell, and those that supported game modes such as -aram. I've also been a progression and hardmore raider in WoW and SWTOR. I play League of Legends casually.
Now about Prime World:
This is a MOBA but it's not just a MOBA.
It has the grind of an MMO that both casual and hardcore players can enjoy.
Casuals might like the city-building and city-management aspects of the game. You build buildings and order them to produce wood, ore, food, silver, crystals, or gold (cash shop currency). These resources can be used to buy heroes (like LoL champions), buy hero skins, buy talents, upgrade buildings, upgrade talents, send heroes on quests at the tavern, or rest heroes at the inn (heroes need to rest after a match or quest).
Casuals might also like the Zuma-type game in the actual MOBA part of the game. On the 5v5 map, you can have 3 laners, 1 jungler, and 1 playing Zuma, which helps your team maximize everybody's XP gain. When playing Zuma, a successful game rewards you with a one-time consumable scroll that you can send to anyone on your team, including yourself. The spell on the scroll, and the strength of the spell, is something you select before each Zuma game. For instance, you could start the 5v5 match and play Zuma to create a level 1 healing scroll for your jungler, or a level 5 AoE damage scroll for an early lane push.
Finally, for casuals, there is also a PvE map, ranging from easy, medium, hard, to very hard difficulty. And by PvE, I don't mean a "vs AI" game, where you're still in an arena but fighting bot players. This map involves protecting a central location from waves of enemies. There are also side quests throughout the "match", such as escorting an NPC down a lane or defeating all of a specific type of enemy on the map.
Hardcore players can enjoy the endgame, because there is quite a grind when you want to pwn with the best in the world. Your city can produce talents, but you are also rewarded talents when you play and especially when you win. Talent rarity is similar to WoW's, where some are junk and others are legendary, going from yellow, green, blue, purple, to orange. Each talent also has five ranks each, and you can, using WoW terms, disenchant all your junk talents in order to enchant your purples and oranges.
Endgame players can also enjoy the theorycrafting that comes with the flexibility of talent and stat builds. Using LoL terms, some heroes can be built for AD or AP (like LoL's Ezreal or Tristana), and some benefit from both (Akali). Most talents give you passive stat upgrades (+7 agility or +2.2 health regeneration), but others give you a usable skill (temporary invulnerability or immobilize enemy or self heal).
I have only three complaints about Prime World.
1) Matchmaking can sometimes fail you horribly (or benefit you immensely), matching up lesser geared/experienced teams against epicced out players. Mind you, bad matchmaking does not always guarantee a loss for the underdog.
2) Disconnects are an issue. On a good day, all my games go smoothly and everybody has good games. On a bad day, half my games turn into 5v4 or 5v3.
3) My biggest complaint is that all players globally play on the same server, and most are Russian, which leads to ZERO communication. The best you can do is to know the game, know every class, have good map awareness, and hope that your team is as good as you are.
Bottom line: I love this game now. I would say it's more casual than LoL, where people rage on you for being new and not executing your skillshots or timing your CCs perfectly. But then again, maybe they do rage here in Prime World and I just can't understand the Cyrillic alphabet. :)