Hey Heirophant and welcome to the forum,
I'm a bit out of my depth at 2000pts, however some of your units are sub-optimal, so I'll give you some advice on that...
Tigurius is good, but you have to be careful about casting powers from transports or from coming in from reserves... One of the good things about Ultramarines is that they have so many different special characters which can change how they play out on the battlefield.
Instead of:
Elites — 8 Sternguard Veterans — 2 Heavy Flamers, 3 Combi-flamers, Melta Bombs — 241 Points
Dedicated Transport — Drop Pod — 35 Points
Try:
10 Sternguard Veterans
- 2 Heavy Flamers
- 4 Combi-Meltas
- Drop Pod
This is more expensive but will mean that your dudes can capitalise on Combat Squads to maximise their damage on two different target types, increasing their odds for First Blood. I tend to think that Combi-Flamers aren't worth it since Special Ammunition already can do that damage type, therefore I'd rather spend those points that lets be do something else. It would be very beneficial to use the Tactical Doctrine when they are firing their Combi-Meltas, unless the target is weak and only requires a few hits to be taken down.
Instead of:
Elites — 7 Sternguard Veterans — 3 Combi-plasmas, Melta Bombs — 199 Points
Dedicated Transport — Rhino — 35 Points
Try:
7 Sternguard Veterans
- 2 Plasmaguns
- Rhino
This is basically the same cost but the plasma effect lasts over the whole game as opposed to one turn. Note that Sternguard are expensive so be careful how many you bring... You may find Plasmagun or Grav-Gun Bike Squads a more effective way of getting special weapons in as they don't have to us a Rhino to be mobile and can get around a lot faster. Alternatively Legion of the Damned Squads are good, as are Command Squads with Apothecary and Special Weapons.
These are okay:
Troops — Tactical Squad — Plasma Gun, Combi-plasma — 165 Points
Dedicated Transport — Rhino — 35 Points
Troops — Tactical Squad — Plasma Gun, Combi-plasma — 165 Points
Dedicated Transport — Rhino — 35 Points
Troops — Tactical Squad — Flamer, Combi-flamer, Melta Bombs — 160 Points
Dedicated Transport — Drop Pod — 35 Points
However you don't need full 10 man squads to make them operate well, so consider dropping a few off each squad and investing in something else.
This is a good choice for most lists, being cheap and durable:
Troops — 5 Scouts — Camo cloaks, Sniper Rifles — 70 Points
Bikes are good, this unit is no exception:
Fast Attack — 6 Bikes — 2 Meltaguns, Combi-melta, Melta Bombs — 156 Points
I'd be tempted to try to squeeze a Multi-Melta Attack Bike in instead of the 6th Bike and some other things.
These are also good:
Heavy Support — 3 Devastator Centurions — Grav-cannons and Grav-amps — 250 Points
Try putting Tigurius in here, then you don't need to worry about silly transport rules
But seriously, get some divination rerolls etc... and these guys will lay down a lot of hurt.
The one unit where if you're going to bring one, bring two:
Heavy Support — Vindicator — 125 Points
Heavy Support — Vindicator — 125 Points
These are a great pair. I'd be scared.
Overall it's a nice list but seems to be a fleshed out 1500pt list as opposed to a 2000pt list if that makes sense. 2000pt lists can be better using a double Force Organisation Chart as it allows you to focus on the parts of the army which you think is coolest more.
The main thing before you "enter the nightmarish dimension of spending and painting" is to really like the army that you're building. Also build it up in small chunks and play it against different lists learning what works for you and what doesn't.
I hope this helps!
Slick Samos