What're your thoughts everyone on Sandalphon? I'm considering picking one up on Saturday to replace King Shynee at least some of the time. Is he worth it? The 60 cost is hefty as hell, but I'm only three or four rank-ups away from being able to afford it. Will x2 attack for two turns be significantly worse than x3 attack for one turn? It matters the most against high defenses, but huge defense numbers don't seem that common in late-game stuff and I'll always know it's coming.
Shynee's big flaws are terrible stats and lack of versatility, and Sandalphon has much better stats and a much more versatile set of traits. His ability takes much longer to charge up though and I often find myself just barely managing to stall long enough to get Shynee up, so that might be a problem too.
This is coming from someone who only has experience using Sun Quan, Izanagi and Shynee, so I'm not sure if it'd apply to you.
First of all, I couldn't stand Shynee's terrible stats and I switched it out for Izanagi as soon as I was lucky enough to roll one. (Though I'm a Bastet user, Valk sadly still does not have god type, when her name was literally Goddess of the White Shield before her ult) but I can tell you the extra hp is really helpful.
Sandalphon's 25 cd is indeed terrible, you can try to casually skill him up a bit when you can no-stone the dungeon. Not sure if it's worth throwing stones at for though.
2x attack is quite a difference from 3x, so that'd depend on the monsters you have at your disposal and how much damage you need.
Having 2 turns is not as useful as you think, most of the time you have to depend on that one time burst with all your orb changing skills and stuff, but if you have two valks it does allow you to do a bit of extra damage for another turn.
High def stuff is not the concern here because they're usually mid-stage stuff and you should be saving the enhance for the boss. There are exceptions though, mainly stages involving tamadras where you can enhance and kill all other mons leaving the tamadra intact (it has ridiculous def so it's ok), and you can proceed to stall for skills and arrange orbs in your favour.
In the end, it depends on whether you need the extra hp to maybe survive that one hit from a certain wave, or if stalling for 25 turns is possible and so on. It's always better to have more choices and flexibility in your team for facing different dungeons.