Nice to see people coming back to the hobby, so welcome back!
Thoughts as I see them:
First and foremost, pretty sure you're using an outdated codex. Many of your points values and some organization allotments are incorrect (lootas are now heavy support, for example, not elites). I'd recommend battlescribe as a free, effective army builder.
• Warboss + power claw and twinlinked shoota (on model): 90pts
recommend 'eavy armor upgrade.
• Weirdboy: 55pts
Level 2 psyker is a nice upgrade. Also, base wierdboyz are 45 points.
Sub total: 145pts
Troop choices:
• 20 sluggaz + 2 big shootaz + nob with big choppa = 23 models, 163pts
• 20 sluggaz + 2 big shootaz + nob with big choppa = 23 models, 163pts
• 14 shootaz + 1 rokkit + nob with big choppa = 16 models, 121 pts
• 10 gretchin + runtherd with grot prod = 11 models, 45pts
Sub total: 492pts
Bosspoles are nice upgrades for units, as ever, and I like power klaws in units of 20 or more boyz. Not a big fan of shootas. Also, some of your points values are incorrect - the shoota mob is 5 points short, and a minimum grot squad is 35 points.
Elite choices:
• 10 lootas + 2 rokkit launchers = 12 models, 190pts
Lootas are a decent choice, but the only way to take rokkit launchas is to include meks and give them a rokkit. Which isn't a bad idea, but don't bring more than one, it's a waste. in any case, the cost for the unit as you described it is 178.
• 4 burnas + free Mek = 5 models, 75pts
minimum burna squad is 80 points (16
ppm).
• 10 Nobz, 9 with big choppaz, 1 painboy + grot orderly = 11 models, 280pts (Warboss’ Unit) + Transport: Trukk @35pts
Painboyz are now an
HQ choice, like wierdboyz or warbosses, so they can be attached to any squad. Still 50 points though. For nobz, I like a couple power klaws, and definitely 'eavy armor.
• 5 Kommandos = 5 models, 50pts
Fun unit, though 5 probably won't get you very far.
Sub total: 630pts
Heavy Support:
• Looted Wagon @35pts per model + Boomgun @ 70pts per model = 1 model, 105pts
• Looted Wagon @35pts per model + Boomgun @ 70pts per model = 1 model, 105pts
Looted wagons have changed considerably, most notably because boomgun became a killkannon, but it keeps its transport capacity and is cheaper. Free rules too:
https://www.games-workshop.com/resources/PDF/Blog/ENGWD021_025_web.pdf
• Total: 210pts