Brink is not worse than Duke. Kind of humorous is that I have both Duke Nukem and Brink platinum but Brink was the better game. Unfortunately, plan on spending about 25 hours to platinum it. Towards the end it is just such a grind to get the last levels to 20 or in my case 24 because of the Agents of Change DLC.
My best suggestion is play the game online when you play through it. That will provide all the levels plus you get the Tough as Nails achievement. I doesn't matter if there aren't people online to play with, the computer will fill in the spots.
Do all the 3 star challenges on a brand new character. Everything they unlock will be available for all your characters and this way the AI stays really crappy as well. If you are level 1 the AI is level 1.
Realize that your teammates are also at your level throughout the game. Basically they suck at the beginning, you will need to do all the work including completing most of the objectives. Once you get to level 15 they will do almost everything if you can keep the enemy away from them. When I played through it with a friend we basically spawn camped the enemy or setup in choke points. We would setup turrets and we both had the Light machine gun (chizznor???). When we did this the AI would take care of the rest of the objectives.
When you get to the end and you have all the trophies except for the one for reaching level 20 then play Container City on Easy in Stopwatch mode. Set the time to 30 minutes and be on the resistance side. You should be able to keep the enemy from even completing the first objective (blow up the gate) because the enemy immediately goes into a choke point where you can cut them down with a Light Machine gun or Assault Rifle. You are also getting bonus points because you are protecting the objective. I could average 18,000-25,000 xp per round on that map. For comparison level 23-24 was about 55,000 xp. So basically it would take about 1.5 hours to do that level alone.
Anyways that is my information on Brink. Is it great? Absolutely not. Is it good? Meh. Is it worth $5 if you want to get a really easy platinum and are willing to grind it out? Yes