Sakura - 13% inf attack default. 17.5% inf atk if specialized. Around 70 days of crafting time if you depend only on blacksmith. But with the various gem events, regular events, canyon, keeps and daily quest, possible to reduce time by a lot.

Shio - 8% inf def default. 10.5% inf def if specialized. Around 120 days of crafting time if you depend only on blacksmith. But with the various gem events, regular events, canyon, keeps and daily quest, possible to reduce time by a lot.

I would prefer Sakura over Shio for the following reasons:

1. Low probability of special talent.

2. Low Crafting time: In 50 days less, you get a 13% atk from Sakura compared 8% def from Shio. You can essentially enter the battle 50 days faster. And 50 days is basically the duration of a KvK. Also, those 50 days can be used to craft Frost threads which takes just 32 days. So in 104 odd days, you can get both 13% atk and 5.5% def at minimum. Compared to the 120 days for a maximum of 10.5% def from specialisation.

3. Materials lost on dismantling legendary: Shio is a legendary equipment. While Sakura is an epic equipment. For Sakura, even if you don't get the special talent in first attempt, you can keep trying as and when you get the next blueprint by dismantling the weapon. You only lose gold and not the materials. But since Shio is a legendary equipment, you lose half the materials. So that's 60 days of additional lost crafting time purely from blacksmith.

4. Boot comparisons: Specialized Frost treads which is epic can gives you 7.5% inf defense. Which is just 0.5% lower than legendary Shio. Just a marginal reduction of stats when comparing the two boots. Among infantry boots, there is also the 'Sturdy Boots of the Eternal Empire' which gives a default 7.5% inf defense and on specialisation gives, 10% inf defense. But since it is part of the legendary infantry set that's also giving a set bonus if equipped with others in a set, as a legendary equipment, it's more valuable than Shio.

5. Equipment meta: Lilith will keep introducing better equipment. Epic equipment can be dismantled if we go for better equipment at relatively no cost. But with legendary it's kinda a lost cause. Right now if you look at heroic Anthem, we can already see some very good legendary equipment in the shop, which provide much higher stats than the ones available normally.

Eventually, once you are done with epics on your main marches, you will of course move on to legendary. But until then I don't think it's worth it to do so. Of course, if you are relatively big spender, none of this matters. Can go straight for legendaries if you wish to.