In the PnP, blade ward and true strike are, legitimately, the least effective and hardest to use effectively cantrips that exist... they're legitimately bad. Bladeward only lasts until the end of your next turn, so you get one round of enemy turns to have resistance, with the dubious inclusion of an Opportunity attacks you take on the turn you cast it, and on your next turn as well. In almost all cases where this effect might be beneficial to you in a meaningful way, there will be better or more effective options for you to use.
Truestrike is worse, since it also consumes your concentration while you hold it, for a single advantage attack roll next turn. If you'd used that action to actually make an attack instead, as well as attacking next turn, then you've gained functionally the same benefit (two attack rolls although with the possibility of both hitting, so, better in fact), without needing to hold concentration.
The changes they've made to these cantrips makes them last a turn longer, so you can actually gain their benefit while you do something else for a turn or two, and I've had times where I've actually used them, albeit very rarely.
As others have mentioned, making them into bonus actions would be exceptionally over-powered for cantrips - but giving bladeward an additional turn of duration wouldn't be a bad idea. Truestrike continuing for *all* your attacks for the next two turns is already, I would say, significantly powerful for a cantrip. It doesn't need to last any longer... Imagine an EK at level 20 doing a quick cantrip to take auto-advantage on eight attacks - that's pretty damn powerful.
