Couple of things:
#1: Combi-melta + 2 Melta is legal -- you simply use Index options, which allows the champion to choose items from the Champion's Wargear section. You use the Codex's updated point values for the CMelta, of course.
#2: Reaper Autocannons are bad for a variety of reasons, and the issue you raise regarding the weapon being a fair "all-rounder" weapon is a little off -- first and foremost, a Blight Launcher is not "Damage 2", it is "Damage d3", which means a Launcher can deal 6 damage, while an RA can only deal 4. While it is true a Launcher has a reduced strength and range, it also rerolls to wound, and can reroll ALL to wound rolls if you have a nearby Arch-Contam. Finally, because the weapon is an Assault weapon, a Blight Lord squad can always advance and fire. The S7 on the Reaper seems like it'd wound T6 a little better than a BLauncher, but this is actually untrue -- rerolls put the BL over the top on T7+ as well. Even better, Launchers synergize with the maximum range of CBs, meaning all weapons can fire on an enemy at 24'', while an RA overextends at 36''. Even versus T3 infantry, a Launcher kills more on average than an RA due to rerolls to wound. Plague Weapon is a very strong rule. The only thing an RA has going for it is higher potential damage on hordes of 1W models with bad saves and bad toughness, and Blight Lords can sleep-walk through 80 Cultists in melee with flails, so..
#3: Starting Lords on the table is probably the worst possible choice to make, even WITH Warptime. They absolutely NEED to DS, 95-99% of the time. You'll curbstomp clueless people with Warptime Lords, but it has the same problem that Grenade strategies have: you telegraph your punches. The enemy knows where the BLs are, and thus where to either avoid, or concentrate force.
Dropping Lords on a weak flank and pummeling squads of infantry with bolter spam is where they shine -- if they flub the charge, they flub the charge, but at least they will be sitting on an objective they DS in on, and continually pounding weak squads at range. They excel in one role: they are durable flank-aggressors who can camp a key area. They are certainly more than competent in melee, but what they really are is (with combibolters, axes, flails, and launchers) infantry-mulching backfield/flank invaders who can also kill anything they can reach in CC.
#4: The role of Launchers on Lords is a simple one -- you have a weapon which can threaten anything in the game, and fire with no penalties. Do not expect them to utterly demolish anything they hit -- they chip away reliably at anything from Cultists to Orks to Knights. Their biggest benefit is their versatility. Sure, you could drop them in a pinch and simply run with 8 CBs + 2 Flails, but I think BLs are $.
#5: Forget swords, they suck. You're already gaining -1 additional AP when you roll a 6 to wound, and you already gain +1 to wound from Blades, and another +1 with VoTLW -- S5 is money, because it means you wound anything in the game on 5's at the worst, and reroll. The reroll makes it even nastier, because now you're able to fish for 5+'s when you have Blades and Vets on 'em. Axes, every time.
I hope this helps.
Edited by DemetriiTZ, 15 January 2019 - 04:00 PM.