Hi, it seems we have a shared interest in Guardsmen falling from the sky.
I've started work (literally first draft, ideas) on my own Drop Troops style list, purely for personal use and can offer humble suggestions (in no way intended to parasitically leach advice from your constructive audience,

).
We have come to similar conclusions about a Drop Troops list being about Guard Infantry 'appearing' about the battlefield, about the lack of heavy armour being the downside vital in making them balanced compared to Steel Legion.
How we've gone about it game-wise differs.
I've introduced 'Grav-Drops', essentially a 'Spacecraft' (you plot the turn they fly over, etc) that allows up to 3 Drop Trooper Companies to Planetfall.
Fluff-wise- a Parachute drop of the size of Companies is pre-planned, requiring pre-prepared drop sites, rallying points, etc.
Game-wise- it gives the Guard player the ability to arrive anywhere on the board, but without the perhaps overpowering ability to choose whenever and wherever as demands. It means the Guard Paratrooper player must have a working plan before landing, rather than just through formations about reactively.
I think it offsets the inherent advantage of arriving when and where you want on the board.
I've also included 'glider companies' or Dropcraft Companies.
Dropcraft 5+ RA. Transport: 4. Bomber. CC 6 FF 6. Heavy bolter 30cm AP5/AA6.
Dropcraft Company is 12 IG. 1 Command. 4 Dropcraft.
-Once landed the Dropcraft cannot take off.
Ideally, once your Drop Trooper Companies have Planetfalled, your Dropcraft Companies fly in to support the attack. The Dropcraft are remarkably stubborn, but once down are pretty much static Heavy Bolter mounts.
We have Demo Charges in common, though I've made them a separate unit:
Sappers- Save -. CC 5+. FF 6. Demo-Charge- 15cm MW3+, One Shot.
4 for 75pts as upgrade.
I figured with a lack of heavy armour, there's a lack of Titan Killer, and MW's to deal with heavy armour- so I essentially 'threw them a bone'. A very short-ranged, limited bone.
Hopefully I've given some new ideas, as your list has to me- I've not considered other versions of Aircraft, or more usage of Valkyries for example.