That's pretty much it. In all honesty, I find that Orks, Chaos and Space Marines all have very similar gameplay. Eldar have considerable restrictions on who can take what wargear. That, coupled with having just one class from seven (rather than either one or two from five) that can capture points, means you have to be very clear on what is expected from you in any given situation when you play a given class. It's quite unforgiving. If you're not sure what you should be playing that will best help the team, you should be playing a Dire Avenger, so you know your team can definitely capture or recapture a point. There are nuances with each of the other factions as well, but Eldar are the most dramatically different.
We really do need more information in game and a proper introduction to each Faction. Not just in game info but a proper back story on each Chapter, Clan and Craftworld. For the non 40K fan they have no idea what's even going on. I hated Titanfall I how you're just thrown into a universe where you really have no idea what's going on and no backstory as to why your character is there, who your character is, who's this guy yelling at me and why am I in this drop ship. They actually had basic info as far as a very basic back story where as inEC you just start the game, create character, and jump right into match without having any idea as far as what you're doing, where you are, why you're there, why your character is there, where you came from, where you were born, your background in your Chapter, Clan or Craftworld, and what capabilities your class and faction have.
Get used to fielding these types of questions, lads. There are going to be a LOT more of them. Exactly. The new players who have no knowledge of 40k are going to be confused by the differences.