I could be wrong but I thought alt only showed weapon ranges. To see the ability range, hover your mouse over the ability icon.

I can confirm this, happened in the exact same circumstances. The titan tried to engage the turrets, but they were outside it's weapons range. It just sat there taking fire.

EDIT: This happened with the Rebel TEC Titan too, while trying to attack an enemy hanger.

Same happened to me, also made a note of it in my own issue thread.

As to the overpoweredness of the titans. I fought an Ankylon titan in another player's own gravity well, and that thing regenerated about 80 hull damage per second. Even though my own Ankylon was two levels higher, I could not bring the enemy titan down and I had to retreat eventually. I think the Ragnarov wouldn't have a big problem with it, and maybe I should've put more ability points in the Ankylon's offensive ability, but I have yet to test this...

Same here. I also noticed this last night when taking out the Pirates.  The Titan would not engage the turrets until I made him get closer .  The other Issues with this Cap ship is, he likes to try and Broadside its targets.  this is ok, but the Beam arrays will not engage. the firing Arcs on the side mounts need to have a little more Fire Arc added to them..  the only way to use Beams is to turn the ship forward.  You end up loosing a lot of fire power when having to use it this way.  The beams need a better firing arc.

Its not invincible, It may seem that way  because your fighting pirates, but taking on the enemy in their own backyard with a star-base upgraded and you will loose the titan.  I ran into this and my titan was level 5  by the time I was able to remove the star-base my titan had only 2400 health left.  I don't see how that's invincible. and I had a small fleet helping him out and that fleet got wasted by the end of the fight.

Truthfuly Im a little suprised that anyone would be complaning about this ship being OP.  The AI is not even working that well currently so given the fact  that the AI is working good and how they spam fleets of frigates, the Titan will find its self out matched if I had tried this tactic with the AI is good working order, I would have lost my titan.  I don't see the Titan being OP. its supposed to be a killer ship and I currently like it the way it is.

Same issues with the Ragnarov. Even giving an attack order leads to the titan sitting around doing nothing quite a lot. 

I believe the Titans are not too powerful, I was playing a game earlier where I was with my level 5 Rebel TEC Titan against a planet with quite a few air craft hangers and a starbase that was completely leveled up. It had 20,000 hull and somewhere around 8,000 shields. My titan had 14,000 hull and 6,000 shield. I had all the abilities unlocked and 2 on the enhanced weapons (25% better), one on antimatter, and one or two on the hull integrity, the rest were spent on the "gun" abilities. I was attacking the starbase, but it was not dying very fast. They also had two repair structures that were repairing the starbase at almost the same rate as I was destroying it. They then sent in about 5 capitol ships around level 4 each. 1 Kol, 1 Dunnov, 2 of the troop transport ones, and one of the big missile attack one (I just can't remember the names lol). My Titan was down to 3,000 hull so I told it to retreat and it lived to fight another day, but they would have been able to bring it down.