In the most general way to summarize this post, we need to minimize the opinions of hardcore fans from the Halo 2 era, and focus more on what will make Halo 4 a modern game with modern characteristics that the community is truly looking for in a warfare game.
Everyone has heard of the term “Halo 2.5” which is simply describing a Halo game that will be created to pretty much be just like Halo 2, and succumb to the will of the Halo 2 fans. Of course, such a perspective on how Halo should be created is not collectively shared amongst the Halo community. Now there’s one thing that is really impeding on the progress of the Halo series:
Nostalgia.
Yes. Nostalgia. That feeling of missing the past. Halo 2 was probably a big moment for most hardcore gamers out there. Many gamers first experience with online/competitive gaming was in Halo 2. It was something you grew up with, and it was something that allowed you to have fun. This is where the problem lies.
For example. My friends and I listening to several bands including A Day To Remember, Parkway Drive, etc… all of which have several albums from different years. For me, I started listening to A Day To Remember when they released Homesick, and therefore, my love for them grew with that album. Due to such love for that album, any progress after that was never seen being better. My friends as well. They found Parkway Drive during Horizons, and I found it during Killing with a Smile. Anything after those albums were looked as not being as good as the original.
Okay, back on topic, ladies and gentlemen.
See how that relates to Halo? We grew to love Halo 2, and our development in gaming was structured around Halo 2, and how we played it growing up. Now we are faced with new Halo games that follow, and with each game, we see it as “not as good”. Is this true? No. Are we reminiscing over the past and irrationally comparing every Halo game to Halo 2 and judging it based on that? Yes.
To save Halo 4, we must clear our mind, and any pre-conceived ideas of this idealistic Halo 2 that we have created. Halo is growing, and advancing, and as a community, we are destroying the growth of its potential by holding it back in the past. In order for Halo to evolve, we must evolve as a community and accept that Halo 4 will offer new and different characteristics from every other Halo game.
Tl;dr - Out with old, in with the new. Discuss.

So from what I’ve heard about it I would like to return to it, or possibly have a similar taste of it…NOT Halo 3’s system or Reach! Please for the Love of Halo Don’t use Halo 3 or Reach’s System!