Thats a great point. The most consistent problem i find with using ruiners offensivley is that it takes FOREVER to line up so it can lay mines, and then when it does, allot of the time more than half the mines are all the way on the left side of the cluster, and the fleet just goes thru the right side.

This is quoting JohnJames, a "pro" rated player.  I have seen him use vasari ruiners to great effect.  He is already a bastard with ruiners and mines.  If you buff them he will become even more of a bastard with them.  In other words, he's the rabbit saying "please don't throw me in that briar patch!" - but that's exactly where he wants you to throw him.

More to the point, ruiners are plenty effective and useful.  One use I've seen JohnJames and other "pros" put them to is forming a "beachhead" at the enemy world.  You jump in with your fleet and then lay mines to protect your fleet.  There are several ways to do this.  Perhaps you lay a cluster of mines to stick your carriers in so that can't be killed by LF.  Perhaps you lay a "wall of mines to guard a flank.  I've also seen people lay a "tunnel" of mines (two walls, with the fleet in between) leading up to the planet.  The fleet stays with the tunnel, and can bomb the planet with abandon, protected by the two walls.  The defender has to try to crack the wall of mines while the invader has the easier job of preventing him from doing that or causing serious casualties in the process, all the while continuing to bomb the planet.

There are lots of other things too.  Protecting a starbase as it is building in the enemy gravwell, etc.  Use your brain, be creative.  I see lots of ruiner usage in "skilled" games.

Don't know if you were in the beta or not.  But the ruiner used to deploy mines in a line.  It didn't "throw" them like you suggest, but it would lay them in a line.  This turned out not to be so great, and it was changed to lay them in a "chaotic cluster" which was deemed much better by everyone (including me).

Also, a few have made the suggestion that mines attack structures.  Actually, mines used to attack structures when Entrenchment was released.  But they changed that within the first update patch or two so that they can't now.  Personally, I liked mines attacking structures, and I put this to good effect as Advent, but perhaps there was a balance concern I was unaware of.  I must say it was a little strange the first time I laid mines to protect myself from an invading vasari starbase, and the starbase went right through the mines to get to me without detonating the mines.  I went back and looked at the change logs from the update and realized mines no longer attacked structures

hehe I love mines.

They were so much better during beta

Right now, mines are all about "are we fighting a fool or not".
A fool/nib will blow his ass off on the mines.
A non-fool will let the mines blow 3 LFs to create a big enough breach and that's all you've won for researching, building, and draggin the slow Ruiner along with you and placing the mines for all the resources.

Your complaint seems less about the Ruiner in particular, and more about all mines in general.  I agree, mines are probably too expensive in terms of the utility they provide.  It's the result of an overnerf stemming from the beta, where people were screaming bloody murder about mine spam.

Not quite.
Mines are fine you just plant them around the phase lane exit, so the enemy jumps into them as he attacks. He has to slow down, clear the mines or else his attack is gonna blow up on it. It takes a little time and effort to work around that. 
When used it defense, the 30 sec activation time or the slow pace of laying minefields is a tiny drawback. The ruiner's low speed and maneuverability doesn't hurt all that much. And there is a limited area the enemy may attack from.
On the attack however, all the above mentioned drawbacks become true nuisances. The time is NOT on your side in an assault scenario, you're not just there to plant some steel nuts around. You're there to either wipe his structures, wipe the planet, wipe his fleet or all at once.
That's what I mean - ruiner is just as good as every other faction's minelaying technique in defense, but it is not really useful in attack. And that hurts, cause it was made to be used on attack.

The best way to use those mines offensively is to launch them at maximum speed into an enemy structure, using the hull of the Ruiner as a protective sabot. Boom!

Kamikaze ships would be a good reflection of how 'desperate' Vasari are in their runaway from the unknown menace.

except, arent vasari hard pressed for ships? they might not want to lose ships in kamikaze-ing

The Advent might.

if all else fails read the instruction manual

1. play advent

2. place all mines in the general vicinity of phase lane exit.

3. park guardians around exit area

4. research repulsion

5. im sure you can figure out the rest.