I'm not a fan of the franchises using really large ships. To me, it smacks of "Look how great my franchise is because I have the biggest and strongest ship!"
I thought the Reaper ships were an adequate compromise. Quite huge compared to a human, but altogether practical and not blindingly enormous. The Crucible was an unwieldy space station, so it being so large made sense.
Just playing devil's advocate here but when you say "I thought the Reaper ships were an adequate compromise", aren't you really just using the ships chart above to make that statement? I mean really in the ME games, the sheer size of a Reaper like Sovereign is epic and made so that it can only leave the player in awe of what the odds against you are. The first time I saw Sovereign on Eden Prime in ME1, I certainly didn't think: "well that's a nice compromise... I should be able to defeat that fairly easily..."
I'd be curious to know how the person who made that chart was able to figure out scale... take the biggest ship on that chart for example... how do you fit that on a TV screen (for gaming) compared to the protagonist you're playing?
Also, remember the T-47 Airspeeders from the Empire Strikes Back? Ships that size probably wouldn't even register on that chart.