You really cannot compare the two games play style at all though. ODST is meant for the campaign, it was never built for a multiplayer... besides firefight.
The other Halo games were built for campaign AND an online multiplayer experience where one team would win. Kind of like the classic gladiator arenas where the last man standing wins. The ranking system was there to help you get matched with people of a similar skill. ODST was not a typical Halo game... you didn't have strong shields, you were not as fast, and you really couldn't jump that high. You are an ODST... not a spartan. You shouldn't compare the two. Heck, they shouldn't even be in the same category.
The ranking system took away from the story line? How? They are two separate monsters themselves. Ranking system is for Matchmaking, not campaign thus should not have any impact on the story line.
So... you play a game where no one really wins (ODST) or you play a game where you compete to win (Halo 2, 3, Reach, 4).
Two different game styles which should NOT be compared.