I enjoyed Mass Effect, but Mass Effect 2 undid my interest in the series.
Mass Effect's locations offered some freedom of movement - they felt like actual places.
Mass Effect 2's settings were extremely constrained by comparison - no longer living locations to explore, but very much tight funnels that might as well have had "== One Way =>" signs posted.
If you mean the ability to land on planets and then spend more time fighting the bouncy vertical movement of your vehicle than actually moving around the map, then yes, I guess ME1 had more freedom. I found them about the same in terms of linearity, but I was very glad I didn't have the bounce-o-matic sessions anymore.
"Levels" (for lack of better word) were extremely "follow the only road" in ME2. Yes, missions generally had a single start point and a single end point in ME1 as well, but the point is that the path from A to B was MUCH more free an unencumbered in ME1. It was, well, sort of the difference between an RPG and an almost-FPS.
What platform were you playing it on? I have the PC version and enjoyed every moment in the Mako - it goes up, down and side to side like a boss, and you don't even have to maneuver around obstacles :-)
PC here as well. Sure, you can drive over all but the nearly vertical mountains... but hit the slightest bump and the Mako is like a superball. Mako was fun at first, but planetside gets tedious fast: loading screen - bounce - bounce - hit anomoly 1/2/3 and do same minigame for all - bounce - short, unsatisfying vehicle firefight - loading screen. ME2 was much better - here's a planet, grab the resources, if there's a special mission, then you get a loading screen.
I had a somewhat similar experience when I played Prince of Persia: The Warrior Within.
I remember it being very pretty, engaging, with wide open spaces and interesting combat... and then you would get to a dead end. You would look around a corner and find the way forward. It might sometimes take a while, but there was always exactly one path through the level (and game!) on reflection.
I would contrast this with some of my favorite moments in Portal: you can either get yourself accidentally utterly stuck (and the game has to detect that and let you out), or you can find clever ways with a risky approach to bypass an entire level.
I guess I'm saying that as a general principle, every level should have at least four paths: one is risky and difficult and unconventional but will lead you to the end result a little bit quicker; one is the longer, slower way; and one looks like the longer, slower way but in fact goes nowhere or leads to a trap; and one leads you to a secret which might help.
(I also appreciate situations like Zelda where you don't tell me what order to complete the dungeons in -- maybe dungeon A has an item which is important for solving dungeon C; if so then consider building the risky-difficult pathways through C to not require this item.)
Mass Effect's locations offered some freedom of movement - they felt like actual places.
Mass Effect 2's settings were extremely constrained by comparison - no longer living locations to explore, but very much tight funnels that might as well have had "== One Way =>" signs posted.