It will become imbalanced if you add HWP carrying ability to it.
It's pretty useful without HWPs.
I would limit it's HWP carry capacity to 2.
The Skyranger can carry up to 14 Soldiers, or 10 Soldiers 1 HWP, 6 Soldiers and 2 HWP, or 2 Soldiers and 3 HWP.
Would be cool if the Lightning could carry the following: 16 Soldiers, or 12 Soldiers 1 HWP, or 8 Soldiers 2 HWP.
So it would be an improvement over the Skyranger in Carry capacity by 2 spots. Despite the ability to arm it and the faster deployment of course.
As for tools - Map editor will be enough (there's a thread with latest version link). No need to alter MCDs.
here
There are no native tools for Linux. You'll have to use wine.
Thanks for the Link i will play a little bit arround with this tool.
Are there any introductions to modelling somewhere?
The Ruleset Reference is cool for modding