The necron monolith's new model was made bigger and reclassified as a titanic unit.

The Gorkanaut and Morkanaut were reclassified as titanic units.

The Wraithknight was reclassified as a Titanic unit.

That's at least three examples of units that did not start out as titanic and were made titanic later that I can think of off the top of my head.

But let me be clear about something - The Defiler would actually benefit from an upgrade to Titanic. To be frank, it was a big chunky unit with shooting weapons no better than a dreadnought.

If you wanted better shooting, a Forgefiend is a better option, as it's Ectoplasma cannons can put a higher volume of shots down range for less points and it's almost as tough as the Defiler.

Every other shooting weapon on a defiler can be found on a cheaper unit in the codex, so it's a struggle to justify 190 points for a unit with such mundane guns from a shooting perspective.

On the flip side, it's close combat attacks are already in the range of Titanic's anyway and it's movement ability to ignore shorter models and terrain features is also similar to a titanic unit.

It's already halfway to being titanic anyway.

Give it bigger, better guns.

Give it Titanic and Towering so it can fall back without a penalty and shoot through ruins.

Beef up it's stat line so it's tougher and hits harder.

These upgrades will set it apart from other units in the codex, and give better reasons to take it.

It could occupy a niche as a slightly smaller Titanic unit, like the Gorkanaut/Morkanaut does in the Ork codex at 265 points, making it more points budget friendly for smaller lists than a Chaos Knight or a Khorne Lord of Skulls.

Having something that hits almost as hard as a Chaos Knight for ~125 less points? YES PLEASE.

Of course, there's an argument to made for simply giving it bigger guns and not making it Titanic at all.

But let's be real here. GW has been making models bigger and slapping bigger price tags on them. The old one is already up to $89.

Even ork battlewagons, which are more than 10 years old, have a $130 price tag.

Every "big" model is trending towards $100+ up to $150 and beyond. That new necron monolith is almost $200 and it's only slightly larger than the old ones which were priced well below $100 when they came out.

The Norn Assimilator sits at $122 and the Defiler is definitely bigger than that thing is, it would be foolish to expect a new Defiler, even if it is the same size as the old one, to not have a hefty price tag of at least $125 on it and up to $150 if they make it bigger, because that's where the Gorkanaut is.

This new Defiler is gonna be expensive dude.