Left for Dead was pretty fun for like 2 days then it's the same thing every time.
I expect this game will be the same.
L4D was. But L4D2 was not. (Partly the former is due to the latter.) But 2 shows the brilliance of the core design that was in the first game because of how quickly they were able to iterate a more complex, larger scope and superior game off of the originals basics. If they hadn't done the first game, they probably wouldn't have realized what they could do in the second after adjusting the tech to handle it. I'm glad Valve sacrificed the first game (and its tech) for the second.
Hard Rain may be Valve's pinnacle sequence.
Evolve, like Titanfall and Destiny and some of these other recent "basics established" games are going to thrive or die on how they iterate off the core idea that's so good (or not ymmv.) And not just in sequels. I personally love Frontier Defense's reworking of the core Titanfall concepts for example, Evacuation sounds like it helps rework Evolve. TF2's continual addition of modes and not just maps did a lot for it before F2P/hats.
I do think that lends itself more to a $20 or less + $10-20 expansions model. Than $60 + $20 maps like Call of Duty does. A number of indie titles have taken this approach of $15 games + free weekends + steam sales + $15-20 total of expansion content to do quite well. The two Sanctum games I heard did very well on this model and even better as they increased the sale discounts.
I think they would need to do like a free weekend when they release the expansions though. That way people can demo the new mode and get addicted and buy it. Or insert one map of the new mode for free or so on with the rest of the maps/mode unlocking when you buy it.
Of course I have a feeling this means you'll go to buy Call of Duty: Advanced Black Ghosts 7 for $60 with domination for $20 and hardpoint for $20 and search and destroy for $20, etc. And nobody will still play those modes.
