That is the exact same as my renegade Shepard in ME1 as well, Adept with assault rifle training. I'm about halfway through that playthrough, well, maybe 2/3's and it has been a lot harder than playing as a soldier, tho I guess it depends on what biotics you actually like using. Now that i've gotten everything useful up to the second rank of the skill, so like throw, lift and singularity, they work pretty well on most things. The only enemies that have really dicked me over so far, randomly, are the drones on the moon base. Well, and the Thorian creepers, but that was mostly because I had no medi-gels and Shep had about 20 HP so I had to go incredibly slowly.

The thing that's really making this adept playthrough harder for me is that the AI teammates have gone totally batshiet, Tali's favourite thing to do is steam into the middle of the enemies and die. Especially if there are multiple Krogan, god damn does she love running up to Krogan.