I was told a long time ago that the point where the Shadow mundus beats the Thief is when you have 70% crit without the Thief. Now this was a long time ago, but since then I've worked on the assumption that the crossover point where crit damage beats crit % is rather high. Thus when talking PvE, so when it's not Mechanical Acuity nor some PvP burst combo we're after, but it is average sustained damage, I've ruled out axes ever since I heard this. Could this do with re-testing? Probably, but you asked about daggers vs. maces anyway, which I agree is the real question.

I believe a sharpened dagger and a precise mace are almost exactly equivalent, when we're talking dual-wield. Generally speaking penetration will beat crit % in solo play, e.g. 1x Skoria has been better than 1x Slimecraw in my own testing against a normal skeleton. So even though Slimecraw is 0.5% better than any other crit body piece, a line of pen will still beat it. That said, I would only go up to ~9.1K pen from gear. The rest has to come from Major and Minor Breach up to 18.2K. This is because not all mobs have 18.2K armor in the arenas, but only 9.1K. Imperial City bosses, for that matter, also only have 9.1K to the best of my knowledge. Your first screenshot is, therefore, overpenetrating in some cases. Skoria, maces, sharpened weapons. Take your pick. You want to hit 9.1K and optimise for the most amount of crit % you can get from the rest. This may mean retaining Slimcraw, but I'm not sure.

A lot depends on your skill layout and sets. Ansuul already has a line of pen in it. A typical trial DD will front bar Flawless Dawnbreaker, but you can front bar the Arcanist damage ult instead, which will add pen from a class passive to your front bar. This will leave you free to slot the Arcanist shielding ult on the back bar, which can be useful in emergencies against world bosses or even to save the day when the trial or dungeon goes awry.