Your list sure is unusual.
I agree with MAVV on the Ranger's Standard. Ironguts are Monstrous Infantry, they don't care about moving through terrain 99% of the time, it's 50 points wasted. If you need to bump your core up then I'd take another unit of 10 Gnoblars with Trappers.
In a 1500 points list I would be looking at a Bruiser Battle Standard Bearer (BSB) and NOT a Butcher. Ogre's suffer with incredibly poor Ld for the most part and to mitigate this the BSB is pretty much an auto-include for most Ogre Players so we can re-roll failed leadership tests. He also adds some nice hitting power to the Army. Definitely worth taking one.
Gorgers aren't all that great to be honest. Well unless you are running a tonne of them with Skrag they are fairly useless due to the unreliable nature of the Ambushers special rule. You could drop him altogether and kit out your other units or Heroes. I'd drop him and the Butcher and take a Bruiser BSB.
6 Sabretusks is also very unusual. Often you don't see that many unless they are accompanying a Hunter. Are they 1 unit, 2 units of 3 or 3 units of 2? Usually people take 2-3 lone Sabretusks to use as chaff drops allowing us to out-deploy the enemy and then send them off on suicide missions to hunt War Machines, Mages or just re-direct enemy units.
The Mournfang unit is pretty much exactly how I run my unit, it's tough as nails and will kick teeth in left, right and center so you have pretty much nailed them. Same goes with an Ironblaster, they are a staple of most armies.
Here is how I'd revise your list to make it better
Slaughtermaster - Level 4, Ironfist, Armour of Destiny, Dispell Scroll
338
Bruiser - BSB, Heavy Armour, Talisman of Preservation
184
7 Ironguts - Full Command, Standard of Discipline
346 (Both Characters go here)
10 Gnoblars - Trappers
50
4 Mournfang Cavalry - Standard Bearer, Musician, Heavy Armour, Ironfists, Dragonhide Banner
350
Sabretusk
Sabretusk
Ironblaster
1500
If my math is correct (don't have the book to be 100% certain but I'm confident this is accurate) this list should hit bang on 1500 points. The general idea is this.
7 Ironguts at Ld 9 thanks to their Magic banner will act as the main hitting force and bodyguard unit for your Slaughtermaster and BSB. They can sit in the 2nd rank safe from attacks thanks to there being a Full Command so long as you deploy them 3 wide. The Slaughtermaster's Ld will also be boosted to 9 thanks to the Standard of Discipline and as he is the General he will then pass his Ld out to all other units within 12". As the BSB is also nearby that Ld 9 will come with re-rolls should you fail any Ld tests within 12".
The Trappers and lone Sabertusks are there to slow down the enemy, act as charge re-directors. Use them like speed bumps in front of your army or in the case of the Sabretusks on the flanks to take charges and leave the enemy exposed so you can counter charge with your Mournfangs and Ironguts. Just remember to keep the Sabertusks at least 6" away from friendly units as if they die within 6" they will cause panic and this can cause an entire Ogre Army to fail Ld tests and run off the board. (Hence the high Ld Ironguts and BSB
)
Have your Ironblaster slowly progress across the field shooting priority targets such as enemy war machines or monsters then when a favorable charge becomes available, send it in for the kill. Many forget it's a cannon but it's also a really REALLY badass chariot. Having it sit still like a cannon is wasting it's points. Due to it's High T & S characteristics as well as a half decent Armour Save it's great and chewing out T3 troops such as Elves, Humans and Skaven Core.
With the Extra spell power from a Level 4 Wizard you should be rolling some of the more favourable spells from the Lore of the Great Maw. Most of them are the buff spells, Trollguts in particular is the best spell in the Lore. Try to lure enemy spell dice out by casting other spells first. If they save their dice for Trollguts this means they are letting other spells such as Bullgorger (+1 S) or Toothcracker (+1 T) go through and this can be game changing. Alternatively you can go the opposite way forward and use Trollguts first, drawing out the dice early in the phase so you can then have relative freedom when looking to cast other spells.
As for items on the Characters here's what I'd do. With the Ironfist and Armour of Destiny he now has a 4+ Armour Save and a 4+ Ward Save. He is also T 5 and can regenerate wounds lost earlier in battle by using Ogre Magic (See Bloodgruel under Lore of the Great Maw). This makes for one tough ass General, another reason why taking Level 4 is beneficial. He also has a Dispell Scroll to stop that big nasty spells from crippling you at the wrong moment.
As for the Bruiser, he is only wearing Heavy Armour but he also has a 4+ Ward Save. As described earlier both your General and BSB can sit in the 2nd rank of the Ironguts if you deploy them 3 wide and 3 deep as the Command models of the unit MUST sit in the front rank. When they reach combat the characters can Make Way and get to the front but they are still able to attack from the 2nd rank using support attacks. This means that Armour for the BSB isn't a major deal but the Ward Save is there just in case. He is also one tough nut to crack so he will stick around for a while and probably dish out some hurt considering he is S5 basic.
These are just my thoughts however, if you have any questions feel free to ask. Hope this helps
