Hi Lord Corellia,
Thanks for posting your list. We're on the cusp of a new edition, so its a good time to be rejoining the hobby. I'll provide my two cents for you to think about and help guide your own decision making process (with the caveat that some of what I may suggest could be obsolete with the new rules)
1. What magic items were you thinking of allocating? You receive one standard, and an additional one per battalion you run (giving you two in your list). I notice you're running a Loonboss on foot - I'd recommend the Clammy Cowl as a good pick for him (-1 to hit for attacks against him will make him more survivable), and perhaps the Moonface Mommet for one of your Madcap Shamans (-1 armour to enemies is also fantastic). You may also want to find the extra points to trade one of your shamans into a Fungoid Cave Shaman - they are really valuable for their Command Point generation and built in ward save.
2. Speaking of your Shamans, what spells will you run? Given how goblin heavy you are, you may wish to use spells like Itchy Nuisance (which will help your Trolls hit first), The Great Green Spite (use your high body count of goblin units to nuke down some bigger threats of your enemy) or Hand of Gork to teleport some of your units onto distant objectives.
3. Gloomspite Gitz army rosters tend to do well when they go all in on one or two aspects of the army book. Either goblin hordes on foot, squigs, spiders or trolls. Whilst I like to mix things up abit on my own lists, I have opts for a list mixed between foot goblins and squigs. I can see in your list you have trolls, squigs and foot grots. There is absolutely nothing wrong with any of these units, but you may wish to look at swapping out some of the trolls or squigs for other choices, such as the Sneaky Snufflers to give extra attacks to your goblins. If you want to keep them in your list, consider what their roles are (Maybe run 2 units of hoppers for their extra movement to allow distant objective capping rather than the extra hitting power of the bounders, as you already have trolls and fanatics to provide that).
4. Endless Spells are fairly worthwhile to consider for GG, especially ones that debuff your enemies (options like Geminids for deubffs, Soulsnare Shackles for movement control, or Mork's Mighty Mushroom for area denial are all good choices to think about). GG are all about scale of economy; we have numerous weak attacks, so anything that can increase their survivability or
Hope what I have provided is some food for thought . Have a play around with your roster and let me know what you think.