ToME: the Tales of Maj'Eyal

TW starts with dual daggers, but it seems to be a cruel joke. They are too fragile to survive close combat, and there is no thing that daggers can do, that bow does not do better.
Besides winner in Vault, there is only two with more than 1/5 in daggers in last 40 winners.

So, are dual wield-focused TW incredibly weak, or I'm missing something here?

Most people tend to go bow/dual-wield early and remove the dual-wield points later, removing those weapons in favor of a stave, and use it to cast spells.

Here is a topic that discusses what you have asked in some depth:

viewtopic.php?f=39&t=38436&p=159742&hilit=temporal+warden+dual+wielding#p159742

As you can see the big consensus is that archery is superior to dual-wielding in TWs. That doesn't mean that the latter is not viable, though. Imo I just think that all the mobility and utility from the spells you get synergise better with archery. And as mentioned in the topic, you end up being a really boring archer playing a very interesting and diverse class.