Here is an issue I've been thinking about a few times.

As many players already knows, its possible to make an ACS attack and invite ANY player to join (used to be only players from ones alliance OR buddy list, who could be invited).

Hmhm... then what about the DEFENDING party one might ask?

Well its still the same old same old. A player can ONLY defend another player against an attack (ACS defence) if the player in question is a member of ones alliance OR buddy list.

How about making it a even chance for DEFENDER aswell as attacker?

I hope a change can be made, so anyone can defend anyone without being on the same alliance or buddy lists - it will add new dimensions to the game, if attackers have to take the risc into account - and it would also be a fair change, so not only attackers have the full benefit of the ACS system.

My few cents.
IQ

it's very bad if you see someone that you could defend but within the targets alliance there is noone that could invite you so you could defend it. there should be something done to make that more easy like a "ally friend for 24h" so that everyone in that alliance could give you the right to defend them, without being invited in the alliance at all.

a general ability to hold when and whereever you want is bad. image you got a low player next to you. you use your sensor phalanx if he has a star on his planet. you see he is attacking with his low level of movement speed. and you can defend against every single fleet he starts.

maybe the initial player that is defending the moon/player under attack can send an invite to whoever he wants but not a free for all.
so A is being attacked by B and C
X ( in the ally of A or on his BL ) defends A agasint B and C, and then X invites Z and/or Y etc... ( not in the ally or BL of anyone of A or X ) to defend A.

i think you can understand what i said not sure as i used lots of letters to make my point

hmm, i think you should only be able to invite people on your BL or alliance, but maybe someone who is defending already can invite people who are on their own BL and Ally.

So in your example: A is being attacked by B and C.
A is being defended by X.
X invites Y and Z
Y and Z don't know A, but Y is X's ally mate and Z is on X's BL

well, as long as it is not a free for all, and still limited and confined and not gets out of hands, fine by me.
so i guess your option is better and keeps it more limited on who can defend and how

lol... think about this situation.... i see a player atacking with my phalanx, the atacker has slow engines, so i can defend that "unknown" player.... send a lot of ships and win the battle. This looks tricky to me.