The feat leaves you staggered, so you'll need to make sure your character functions just fine when restricted to a standard action. The feat expenditure will also make it difficult to build a ranged attacking character since those tend to be very feat-hungry builds.
Goblins actually do make good spellcasters, but with that Charisma penalty they ironically lean more towards spellbook-oriented classes like the Wizard, Magus, or Alchemist (which puts their mechanical strengths in direct conflict with their Golarion lore). There actually is a lovely goblin-specific Alchemist archetype called the Winged Marauder that gives you an animal companion in exchange for mutagen at the 1st level. As the archetype name implies you're locked into a flying animal companion, but that's not exactly a bad thing in my books.
Another option is the Oversized Goblin which gives you a Str/Dex attribute bonus, which would be a great option for a reach attacking build.
Also as a side note, Roll With It says that you can move up to your speed if you get hit. So if my speed is 30 and I get hit for 31 points of damage what happens?
The way the feat is phrased, it looks you can choose how much damage you convert into movement. So you could attempt to convert up to 30 points of damage to movement in that case, but the remainder would be dealt normally.
a goblin witch sounds thematically appropriate to me.
Druid (Nature Fang, Druid of Gorum)
Race: Whatever you want
Chaotic Neutral
Domain: Crocodile
Familiar: Protector archetype
Trade away Death Roll (domain ability) for Divine Fighting Technique (Gorum's Swordsmanship)
Use Slayer talents to pick up Ranger Combat Style (Gorum) for Vital Strike @ 6th level.
Maybe accomplished sneak attack to up your dice when flanking with summoned ally.
Have fun getting knocked back and still being able to charge the next round, with Vital strike at the end of that charge.
If only Branched Spear could be thrown (without throw anything).
There is the throwing property, although you really need the returning property as well to make it viable, so it does cost an effective +2.
Or you could take Quick Draw to just quickdraw a dagger whenever you want to throw. Adjusting your grip is a free action, so you can let go of your spear with one hand before you start throwing daggers and re-grasp it when you're done, so wielding a two-handed weapon doesn't interfere with dagger throwing.
... and then throw a knife on the turn you're staggered?
Or you could just charge them again...
A staggered creature may take a single move action or standard action each round (but not both, nor can he take full-round actions).
If you are able to take only a standard action on your turn, you can still charge, but you are only allowed to move up to your speed (instead of up to double your speed) and you cannot draw a weapon unless you possess the Quick Draw feat. You can’t use this option unless you are restricted to taking only a standard action on your turn.
A lot of people miss this bit of information...
If only Branched Spear could be thrown (without throw anything).There is the throwing property, although you really need the returning property as well to make it viable, so it does cost an effective +2.
Or you could take Quick Draw to just quickdraw a dagger whenever you want to throw. Adjusting your grip is a free action, so you can let go of your spear with one hand before you start throwing daggers and re-grasp it when you're done, so wielding a two-handed weapon doesn't interfere with dagger throwing.
There's also the sharding property. A full +2 but you can make full attacks with it, you don't have to wait in the same square for it to return (very relevant when using Roll With It) and it looks cool.
A bad touch cleric really only needs standard actions. Rolling around and slapping people with Touch of Bloodletting or the Chaos domain ability Touch of Chaos could be fun.