A very tiny example of things 343i can do to safeguard the spirit of Halo:
story expansions
alternate endings
extra side missions
new cut scenes
weapon skins
timed exclusives
armor permutations
vehicle skins
achievements
multiplayer maps
character voices
new difficulties
new game modes
upgraded texture packs
extras like commentary and unreleased media
expanded stats
online record keeping
emblems/patches/titles
daily/weekly/etc challenges
access to easter eggs
special campaign and co-op loadouts
throw some of those rec cards in non PvP modes
hell, throw them in ALL the non PvP modes
...and many, many, MANY more choices

and

The one and ONLY thing 343i can do to utterly destroy the spirit of Halo:
pay to win micro-transactions

The problem we face now is a combination of:
Ass holes with money to burn that want to cheat by gaining an unfair advantage in game but normally wouldn't be allowed to due to a long standing history of modding bans and game rules made and enforced by the game makers.
and
Companies who are so greedy they would rather support the above group than support honest players and the previous game makers history of combating ass holes who try to gain unfair advantages for almost a decade.

What a match made in heaven.