It's obviously a negative point ;-) I think the best is having 1 pact with an alliance that is not on your ocean and they will go conquer in one direction while you will go conquer in another direction
I think it is negative to have a lot of pacts. I know pacts help when you are getting attacked and all, but you need to make enemies to get ABP. Too many pacts means no one to attack an no one to conquer. Additionally, having too many pacts may be hard to handle and can get out of control. I would recommend two pacts.
First off, if you go around pacting the entire server, you have no targets to conquer, thus it's going to be pretty boring - you will most likely have a lot of aggitated players sitting in these alliances, which can only result in people either leaving and starting an alliance for their own, or people violating the pact terms.
Secondly, I doubt the alliances that are pacted now have any idea of what the other alliance is capable of; will they have to help them out with every single thing, or are they the best around on the server? You can't tell this early in the game.
You should only pact another alliance when it's absolutely necessary for the prosperity of both alliances; I'd recommend one, maybe two. Anything more than that will be detrimental in the long run.
I would recommend having two pacts. More then two pacts is useless. Alot of people say one pact, but I say two because what if that one pact dissolves or gets conquered, then at least you have a back up.. You need some enemies to get ABP, so don't get no more then two allies.
I think pacting can be a good thing. For example, make a pact with one alliance based in every other ocean. Everyone will still have plenty to conquest for a long long time, but no alliance is going to stomp out a circle of pacted alliances spanning the entire world. Just a thought.
Sorry if this is a rather ignorant answer - I have only been playing for a month or so. I think it depends largely on the leader(s) who make the pacts. Also consider that each alliance that you make a pact with have certain conditions with THEIR pacts of agreement - so the increase in support and defense may be an almost diametric opposition to your interest in expansion (conquering) other cities (if that is your interest). Some of the largest alliances in the game have been hounded to expansion by necessity - their ocean gets crowded. However, that's usually when things get interesting, no?
Ah, what a wonderful subject This is what I tell everyone who asks me to pact with SFB in-game. We have a long standing pact with a worthy alliance that was formed soon after the server started that we would stay out of each others way for the majority of the server (winning or failing) until a single (or multiple) reasons agreed upon by both sides came into play. At this point a notice would be mailed to the diplo or leader of that said alliance with a 2 week notice to terminate the pact. After that period, any action by either side can take place.
Now another grepolis diplomacy scenario is a NAP where both alliances agree not to attack each other for a certain period of time agreed by both sides. At the end of that said period, the NAP can be renewed or broken diplomatically. A NAP option allows a less committed cease-fire, but can also lead to many complications if it is broken abruptly.