i cant think of any modding tool that i use, has been made by a active developer for Openxcom so i cant see any Copyright issues
You cannot modify any of original files. Otherwise you violate copyrights.
Yes, there are lot of modifications of original files, but all of them are violative. The thing is copyright holder doesn't care on this old project. Nevertheless this is violation.
Game should always support original format even if you do create any New format as well
Agreed. And I wasn't saying something like "we should get rid of old format support". Those "classic" loaders have to be used until 1.0.
if we are going to reinvent every format we should just plan to move towards 3D game also.
1. No matter are we going or not - old formats are non editable and are not extendable. Thus in order to keep them intact, we have to invent our own which will be
mod-friendly.
2. Not necessary to go towards 3D. Classic isometric view is fine and with bitmap sprites could look much more crisper than 3D. Though, combination of different weapon, armor, appearence and animation of units will be a pain, and hybrid engine with 3D units in bitmap surroundings is preferable (example - Sacred 1).
How can i create some new Loft template to better represent new items
The answer is - this is allowed only for new tiles. If you modify any classic tiles in that way, what everyone is used to - will be ruined (break expecations), it simply alters gameplay, and possibly violate copyrights. BTW, my proposal of making pathfinder better with inventing new tile "markers" also violates and breaks things.
So, adding new tilesets (with absolutely new tiles) should be done using NEW tile format (which isn't invented yet). I believe, noone is allowed to modify/improve old tiles (not just because of copyrights, but in sake of keeping gameplay classic). Instead, artists/modders have to re-create them from scratch, and replicate maps using those new (or better to make new maps).