My Thoughts on CO's Appeal

Note - I'm not going to write a 100 page thesis. I'm only writing what I feel is relevant.

It will probably mainly attract serious min/maxers (due to the convoluted system), collectors (due to collectable equipments, which requires grinding through quests/instances at end game), grinders (see collectors), casuals (what doesn't attract casuals as long as there's solo elements?), and maybe crafters (there's a simple crafting system, see below). And people who really, really, really like character customization, obviously.

It is unlikely to attract serious PvPers (see below on Combat and PvP), Explorers (since there's very little to explore and most traveling will be done because of quests), Epic Story Lovers (because the stories from quests in CO is disjoint and mostly unrelated to one another), Immersion Lovers (because the open world is practically static with few dynamic fluff events, spawns are at static locations, etc.), etc.

Some of the main aspects are described below:

Combat - It's fairly simple and straightforward. Anything affecting a target will require a target unless it's a Point-Blank Area of Effect. You have your Endurance builder, which is essentially an auto-attack (And you shouldn't turn the auto-attack off unless you want to be less efficient) to give you endurance so that you can use other powers for a few seconds before coming back to the Endurance builder. You have powers that do knockback/knock-up/knock-down/repel and powers that apply holds on the target; and most of these will give the target the respective resistance to the type applied for a duration. There's practically no  predictive element to combat. Even though reflex plays a small role in the game, it's no where near the amount necessary nor as demanding as in games like Guild Wars. However, during Closed Beta, many people who enjoy the combat, enjoy it due to the animation of the powers, since it makes them look cool; and they don't play to be efficient (i.e. - relying on 1 strongest power), but switch through powers to look cool or fit their concept.

PvP - You have Duels and simple Team Arenas (and Free-For-All at level 21+). You can't really pvp alone without pve, because leveling through pvp is much slower and you don't get any worthwhile items, which will start making you weak in comparison to others. Balancing issues is still going on. PvP is fun if you like dominating other players (assuming you built yourself correctly). This is possible due to balance issues between powers and how important stats are tied to specific powers; in other words, if you build yourself correctly, you'll be drastically superior to another person. Currently, players can only undo up to 10 points applied to their character, so a gimped character will remain gimped.

Quests - It feels like the stuff from WOW. You go to a contact. Take a quest. And go finish it. Return to contact and return the mission for experience and loot. They're pretty much fetch or destroy missions. There's some instances where there's more to them, where trivial puzzles become a part of the game (e.g. - use this magnet through glowy objects to collect this and put into this).

Leveling - pretty much exclusively through quests. PvP gives like 1/2-1/3 the rate of PvE. Mobs give hardly any experience and is much worse than PvPing.

Crafting - there's really only the 3 distinct schools. You're not going to be particularly special. And crafting is beneficial (in the later levels) and easy to level enough that everyone should do it.

Teaming - You have to go out of your way to find the teaming UI. For this reason and others, there's hardly much people using it. The game is also fairly solo oriented. It's possible to solo through everything, assuming you build yourself like a tank. Also, teaming feels awkward, since everyone is usually built to solo, so it doesn't ever feel like you're working together. It feels like we're soloing together. Of course, not everyone will feel this way, but I certainly did and others mentioned it as well in the Closed Beta.