Last fight I saw like that, the titan disconnected partway through the fight and the hunter ships got to shoot at a sitting duck for about 5 minutes. That's not the kind of advantage I really had in mind.
The math says the titan should be able to one-shot the first cruiser (which makes it now 2v1 instead of 3v1, let's say), tank the next 2 for a minute while its big guns reload, two-shot the second cruiser, and then stand off against the third with low shields. The third cruiser dies a minute later, after possibly getting a minute to chew on the titan's internals.
I admit I am a little bit of a newbie, so why not share your experiences? I would really be interested in some anecdotes that substantiate your claim.
I'll freely admit that I am not the person to go to for first-hand PvP experience. I'm a thinker and a builder, not a fighter. What I
am good at though is listening too and remembering other peoples experiences. So for first hand knowledge, there are other people you should ask, something that I encourage you to do rather than just taking my word for it. I can promise you that most of them will back up what I have said though.
Anyway, what I
do know is that the power curve means that bigger ships are less efficient. So there's a big boost to a smaller craft right away. Addressing your specific scenario, killing a ship in SM with a single shot is almost impossible, as long as you don't do anything silly like spam aux reactors. It's not
completely impossible, mind you though. To do so, however, on a ship about a third of your own size, probably is, unless you dedicate your whole ship to the biggest missile/pulse/explosive you possibly can. Now, let's say this hypothetical titan does that. Simple solution: lots of PD. A few PD turrets will easily deal with a missile/pulse, and a cruiser-sized ship can fit plenty. So assuming the smaller ships are well designed, this mega-alpha titan is probably sunk already. Alpha strike oneshot missiles were the meta a long, long time ago, but the effectiveness of PD, as well as some other changes, mean it's not a good strategy anymore.
So, your cruiser squadron has successfully negated the titan's main weapon. Now, onto it's tanking ability. As long as your three cruisers equal roughly the titan's own mass between them, and assuming you are equally well designed, you will, between you, have greater DPS and shield regen. That's just how the power system works. So it won't be able to tank you forever.
In short, the alpha-titan strategy is a poor one. Even assuming it did work as you said, it could still be easily defeated just by replacing the 3 cruisers with a bunch of frigates, as the alpha-titan could still only take out one per reload, and doing so would remove a much smaller portion of total DPS.
For a more sensibly designed titan, the three cruisers will just have higher power output, meaning more DPS and shields. This is, again, assuming that they are on a similar level of design skill. A really, really good titan builder who min-maxed everything would probably beat three just ok cruisers. But that should be expected.
The whole regen+alpha strike theory to remove enemy DPS as quickly as possible is sound on paper, and it works in some games, but in SM it just tends to break down due to lack of single shot devastation capability and also the fact that, unlike in say most RTS games, a ship actually loses function as it gets damaged. So while in an RTS game a massive ship can often bet better than a swarm of smaller ones with the same total HP/DPS because the large ship will have the same DPS no matter how low it's HP, while the small ones lose DPS whenever one of them dies, in SM, damaging a ship will cut power lines, destroy turrets, Ect., making that theory much less effective, as a big ship on 50% HP will have lost a similar amount to the swarm with 50% of it's ships lost. The big ship still has shields of course, which allow it to take damage without losing function, but these are limited and in closely matched fights it will often end up that the ship that can take more hull damage is the winner.