No, I mean it, you're just making it needlessly vulnerable and dangerous. Those poor TVS diodes will explode as soon as a mains surge hits the thing. They're frail at those voltages.
It will fail. Maybe not today, maybe not in ten years, but you're cursing some poor bastard who builds/buys it and plugs it into their dirty power, and it blows up while they're out at work and burns down their apartment and all their neighbors have to suffer their mistake (or something hyperbolic like that).
(It takes a big fucking TVS to handle mains transients, typically over "30kW" rated (versus the "1.5kW" parts shown). Those suckers are expensive, too. Upside, they don't wear like MOVs do, as long as you never exceed their ratings. Which isn't the easiest thing to guarantee, given the random nature of real surge events, so you may wind up using many together (even more $$) to ensure that.)
And anyway, you've got transformers! What are you worrying about the common mode voltage? That GDT + MOVs will keep things well within the typically 2.5kV rated range of anything safe to plug into the wall! Just the MOVs would be fine, even kind of overkill as the transformer itself is capable of limiting transients to a fair degree...
FYI,
Tim