Waves C6 and the L3 multimaxmizer are part of my master chain. The C6 is more/less glue and I adjust this very little from what the default 'mastering' preset offers, and the maximizer for hard limiting and priority (using the bands for EQ gain/priority). If I want to further smooth the mix I stack other plugins (an early EQ in the chain, other compressors, etc). It also helps to experiment with what order you're applying the plugins, I would never put EQ last or the hard limiter first, for example. I wouldn't say it's "easy", since you still need to know how to get what's coming from the speakers to sound like you're imagining/hearing in your head. The skill is understanding the tools, and not needing to reinvent the wheel every time you sit down to mix. Otherwise it could take days or weeks to work on a mix that would otherwise take hours with the right understanding. There are certain rules that, if broken, will yield poor results immediately. Knowing those pitfalls before you start a mix saves time/effort.
More importantly I upgraded my sub recently, so now I have a hard crossover (filter) from the sub to my monitors and can get very surgical with the bass frequencies if I want. Much of this is done while tracking and mixing. But I needed the right playback tools to even start producing the frequencies I needed to hear to adjust. On top of this, poor acoustics in the room will further color and disguise issues.
Most mic'd instruments get some degree of roll off below 100hz, bass guitar gets specific EQ treatment depending on its role in the song, and drums get a room reverb with a short t(r)ail so the kick isn't too boomy. I don't produce a lot of metal nowadays, but even on harder tracks I would still have some type of lower end cutoff so the guitars and bass weren't stacking in the lower end. Simple EQ notches for each to sit in seems to be adequate. Just a few things off the top of my head I use to manage the lower end BEFORE mastering.