I've been running the game through with my arsenal merc which is lvl 42 atm and its been too easy. Ive put all my skillpoints to pve-focused skills, kept my items upgraded with cybertech-made parts of my level and everything except heroics can be soloed without Mako or any other companion without any problems. I only free Mako from running crew-missions, when i solo heroics or go into boss-fights. Death from above knocks out all normal packs of 3-5 enemies with one hit and if it doesnt, sweeping blasters finishes all the remaining enemies before they can even get up. Same thing with mixed packs or bosses with minions. Only enemy left alive after DFA is the single strong one who then gets facerolled. 3 x Tracer missiles, heatseeker, 2 x tracers, rail shot (unload everytime it procs). Rinse and repeat. When heat gets capped, vent heat. Ive yet to meet a boss that is still alive when vent heat is used and heat gets capped again. I usually start the bossfights with DFA if there are minions, and stun after that. If no minions, only stun. When stun runs out, i use shield. If boss is ranged i run up close to them, if melee they run to me. Use the pushback to interrupt one bigger channeled or cast-timed hit. If there are two or more strong enemies, i CC one and nuke one down as fast as possible. Its all about gear and level. Have a day for PVP to get some xp so that you are always 2 lvl:s higher than the mobs.