I've actually started playing MPO1 again, and looking at the level design, I'd rather have a linear playthrough like MGS3 or something, rather than these pseudo-open-ended maps.
As in, get from A to B, but you have a choice of taking paths 1 2 or 3 to get there.
And, make most of the multiplayer Maps different from the ones in Story mode. There's only so many times you can visit the Silo Entrance without being able to navigate it with your eyes closed.


My Ultimate MPO2 Wishlist.
1.STORY MODE
-The Story needs to show Big Boss becoming the antagonist, or the events that lead up to it. It needs to be involved, and just as good as any console MGS.
-Could be set during the Liberian Civil War.
-Linear, long game play like MGS3, not mission-based.
-More than just 4 item slots in Story mode, fits in with the long mission.
-Put the army management into the background, and focus solely on Big Boss.
-More in-game dialogue.
-New Metal Gear, transitory between RAXA and TX-55.
-A constant war, battles going on at all sides… maybe?
-New Bosses with interesting and involved back stories
-New maps that are detailed and interesting, taking advantage of different moves from the MGS universe.
-Enemy soldiers that fully work together as a squad to take you down.
-Plot twist after plot twist, double-and triple-crossing. Ocelot has to play a larger part.
-The higher the difficulty, the more secrets revealed at the end of the game.
-Varied environments, including Jungles and swamps, proper urban zones, and subterranean caves
-Traps like spiked logs as well as laser-activated trip bombs
-Random hazards in maps, like twigs to be stepped on to alert nearby guards.
-Makeshift weapon creation


2. ONLINE MODE
-Create-a-Soldier Mode
-6 weapon slots instead of 4.
-Option to disable autolocking completely. Autolock does not make for a good online game.
-Cut down the lag as much as possible.
-New game modes, such as Defend the Base and others
-Poses that are activated by 2 or more people.
-Team support- give ammo or a weapon to a team mate in trouble.
-Enhanced CQC, where players can initiate chokeholds. The player being choked can struggle to free themselves.
-10-player online modes, with dynamic map scaling.
-New, unique maps not found in Story Mode.
-A Lobby chat room, organise matches without having to enter one.
-Expand the friend/black list to about 50 for each.
-The ability to change your weapons/equipment in infrastructure mode.
-ONLINE CLAN REGISTRATION
-The ability to change your username (though still limited to 3 accounts)

3.EXTRA FEATURES
-Unique Characters
*Every single character from every game (as non-canonical Bonuses)
*Young versions of later bosses/characters

-If the squad based play of Story Mode remains, make it so you can issue basic orders to your active squad members.
-No More S A B C ranked soldiers.
-Different FPS screen filters. Snake’s eyepatch covers the right fifth of the screen, etc.
-More standard animations, like rolling, running, dying etc
-Create-a-soldier mode
-Crazy Minigames unlocked by beating the Story mode on higher difficulties
-Weapon upgrading/customisation system. You can make several versions of each weapon, and if the soldier holding it dies, you lose it, though you can create another.
*Rate of Fire
*Ammo capacity
*Recoil
*Suppressors
*Accuracy
*Zoom Scopes
*Range
-Co-operative Story Mode, with extra areas and objectives.
-Super Infinity Mission- Starts out easy, then gets progressively harder, infinitely. Can Fulton out at any time.
-Game (and features) are printed on multiple discs.
-Pre-game quizzes determine what difficulty you start on
-The ability to use the pistols present on character models.
-Crouching run- not as fast as regular run, but you stay semi-hidden.
-Ability to change firing modes of weapons.
-Pre-backup alerts don’t count toward the final score.
-Bullets now leave marks, and explosions leave large scorches in the ground/walls.
-Blood sprays are included
-Special hidden weapons located in secret areas. These weapons will only come from the secret areas.
-New character models.