In my opinion this change would make the use of repositories much better and interesting for everyone:

1)

The 3 buttons on repositories must be active even when the repositories are Vacant

(ex: https://image.ibb.co/dnSXkq/repositories-change.png ).

So, you can spy and attack also Vacant Repositories (the reason for this will be explained in the following points!)

2)

The strategic units used in the repositories not only improve the defensive characteristics of the specific defensive units connected to them (ex: 1 Terminator + 100 scout) ... but they also give the ability of invisibility to the "group of units" sent to collect the resources on the repository!

Of course if a strategic unit is capable of strengthen up 100 units but you send on a repository 101 of them (or more) with the strategic unit (ex: 1 Terminator + 101 sapper), the effect of invisibility will not happen in that repository for this group of units! (the surplus soldier will nullify the effect).

Obviously you will get this effect back, sending 2 Terminators and 101 up to 200 sappers, 3 Terminator + 300 sappers, etc.

3)

we clarify what is meant by "Invisibility" : simply the repository will be shown as "Vacant" (both on the radar and on the map), although your units are inside it and you are collecting resources from it.

However, if a player decides to recon, attack or occupy that repository (which looks like "Vacant" in his eyes), he will reveal the whole truth through his report (he will find out if the repository is really empty or not ... and who is the occupant of it!). He will have these informations even if his attack / recon / occupy fails! ... although obviously, failing to recon, he will not be able to see the amount of Def-units contained inside the repository, but - as it happens now - he will realize that the repository is not empty (as shown on the radar) and he will realize identity of the player hiding inside that repository.

That's all!

By exploiting this new ability of strategic units, for players who collect resources there will be more chance that their harvest will be successful, moreover they will feel more secure in this new situation and so they will send many more units on repositories and they will occupy a greater number of repositories ...

in the same way, even those players who usually use repositories to attack other players (in order to get PVP points), considering the greater confidence of "collector-mining players", they will have more chances to find and hit a player and even seeing all the Repositories mark as "Vacant" on the Radar, for "Offensive-Players" there will always be hope that one of those repositories (which only apparently the radar shows as Vacant!), is actually full of units (ready to be destroyed !!).

All he has to do is just personally check if these repositories are actually empty or not!

Thus everyone will be satisfied by this change and the game on the repositories will be re-launched in a great way! ... and it will become much more active, alive and sparkling compared to now (which is becoming more and more dull, off and inactive).

This is a very simple change: you just have to change some graphical aspects on the repositories (always showing the 3 buttons, even when the repositories are vacant) and ensure that the strategic units confer this ability (the invisibility on the repositories, in addition to defensive upgrading) to the units with which they can be "connected / linked".

If all the units that make up the group sent to the repository are under the influence of strategic units, then the invisible effect will be guaranteed.

On the contrary, if the quantity of strategic units sent is too low compared to the "ordinary units" with which they can be linked (and therefore some units remain outside the effect conferred by the strategic units) then, in this case, the occupied repository will be visible normally on the radar from anyone.