Ill start on the
hq's.
biker boss- he's great, but the boss pole needs to go on the bike unit, otherwise you have way to many eggs in one basket, this guy goes down and you lose
ld 9, your bossppole, nd your
pk. I would spread all that out in the nob unit.
Grotsnik- he is OK, paired with
manz is the best use I've found for him but even then he is mediocre. You pay 160+ points for a painboy that lets your meganobz live 1/3 of the time. Most of the time in this edition they are going to have their armor save or be killing whats killing them. And worse then that he takes up an
hq slot and ork
hq's are terrific. (a
kff protects vehicles for cheaper, a mega warboss makes them scoring, a warphead is a great psyker(for me at least

ghazzy is a beast, etc... ) That being said grotsnik +
MANz is still the best way to run him, and if you like it give it a try, but it might not be the most competitive thing ever but
ymmv.
Elites
mega nobz- hard as ever, put them in a wagon though for reasons already given and watch them krump. skorcha's are good but drop them if you need points elsewhere. However one wagon and only light vehicles elsewhere, smart player will sink you out of points fast. More wagons is better.
tank bustas- they are good and fun, however the way you have them they are way to easy to kill, one round of bolter, a voller of lasguns, even a single heavy bolter might send them running. There needs to be more of them.
lootas- they are great on paper, dakka as a whole seems to love them, but every time I field them, they stink so I really can't say on these guys. Would i run them? no. Should you? maybe.
ymmv.
Troops
shoota boys- great, nough said.
nob bikes- beautiful there model and gameplay are both beautiful.1 more
pk is nice though.
heavy support
Looted wagons-I like these, a s8 large blast is nothing to sneeze at. ard case is good, makes it hard to 1 shot. With a mek you can even sit him back behind these out of
los giving them a coversave and fixing hull points. The big shootas are useless however except for with weapon estroyed results, but I don't see it as worth it.
Big gunz-good and cheap
There is my synopsis of your units. As a whole this list seems like it doesn't have enough going forward, and it doesn't have the
raw firepower to shoot people off of objectives. one model on an objective out of
los and you are out of luck. a more agressive list or a shootier codex will give you trouble. Orks can only shoot so much. Ork shooting is good but still not as good as many other armies or as good as our assault. Good luck.