It seems to me, that you will basically need to pick between being more complicated to play or to build. Also, does a Paladin interest you at all?
The humble fighter can be simple to play, but you have to put a good deal of thought into making him. If allowed, another thought is the mutation brawler archetype. It replaces one of the more complicated class feature with an ability that is basically the mutation ability of the alchemist.
Human Ranger with Falconer archetype.
Take Spirit's Gift feat (Life spirit) to grant your animal companion fast heal 1.
Alternate racial trait for human-eye for talent, make your bird even better...
Focus on archery, while the bird helps your fighter-types by flanking and distracting, while you contribute good ranged abilities and have decent skills WITH some spellcasting.
This build seriously takes off at level four, when your animal companion stops having half hitpoints AND you get spellcasting.
Well first of all an oracle can be a decent frontliner when built to do so, an inquisitor is a divine martial mix who has skills. I'm not sure how the bards fight (ranged or melee) but gunslingers are very simple when it comes to what they do generally speaking, plus you would have a ranged martial character. A capable ranged fighter is always nice.
Playing slayer could be fun. Th err y can work well as a frontliner.