Question about ME2Recalibrated Mod

I don't agree with that. Canonically, the Arrival is already underway by the time you do Horizon- because Kenson has already been missing for a few days by then, and object rho was already counting down before she disappeared. Moving all that to after the Suicide Mission changes the established order of events. The only reason it barely hangs together is that Bioware had to accommodate all the people who bought the DLCs after finishing the base game.

That said, I wouldn't actually care that much. Doing Arrival first is a matter of taste, and I know I'll get downvoted for departing from the decreed Only Correct Play Order as set out by the Arrival-last enthusiasts. But I don't care. For me, Arrival should be bone-crushingly difficult and that means not doing it when you're leveled up. It's just too easy late in the game. You also pick up money and upgrades during Arrival, with no way to use them if you do it last. Finally, the Suicide Mission is clearly the climax of the game so I prefer to do it last.

Forcing me to do Arrival last actually removes content. I can never see the Collector General hologram, and I think some lines of dialogue are different too. That seems counter to the idea of including as much cut content as possible.

Sometimes cut content is cut for a reason. The squadmates you can recruit this way are not fully integrated into the early parts of the game, which means it was a relatively early decision to have it this way, considering how they bothered to add something else in its place. You know it's reaching when very specific workarounds are needed for it not to break.

Think you'll need a source on that

The game was clearly designed to have a second act post horizon, saving a major location for that act seems like a reasonable decision

Only disc space they saved is for potential audio lines