For one, I don't even find Assassin comp to be this end-all, be-all. They can be strong, but a Phantom Dancer on the correct target for the enemy can make life difficult for them. I think the two strongest tags right now are Wild and Nobles; Wild for the easy-to-access Attack Speed buff which is useful on literally anyone and can transition into multiple setups (including Sorc A Sol, which is really strong), and Nobles because most individual Nobles are good and they have an insane late game if you can find a Kayle. Rangers/Knights are also quite strong. The weakest are probably Pirates (too hard to get 3 right away for your early econ when you need them most, literally only useful for money and provide no combat utility) and Gunslingers (pretty much only work if you stack Lucian, Trist, GP and Graves are ok but a little weak and MF is too hard to get even a two star). Assassins are somewhere in the middle, good with good units but can be potentially countered by positioning and PD. Sorcerers and Elementalists are solid too, with Sorc I feel being underrated since 3 of them make ALL units have stronger spells; I've run an Assassin comp with Sorcerers and Demons before, my stacked Eve was nuking people from half health with her ult. It was a really odd and fun composition.
Secondly, I don't even see a point in going 8 Glacials. Sure they each get the proc, but when you're already at 6 units with 45% chance to stun, that's more than enough to proc it plenty of times (along with each of their ults, Ashe and Sejuani in particular are some of the strongest CCs in the game aside from maybe Pyke or Yasuo). Also, even with a Frozen Mallet, how are you getting 8? You have two Frozen Mallets? Maybe you could have used those two Spatulas to put an extra unit on the field. Or maybe you were going for 7 Glacials actually? Again, Frozen Mallet is one thing, but when you're that late in the game I think those extra slots are better served by having other synergies on your team. Kindred is a great start to synergize with Ashe, and Kindred also pairs with a Knight in Mordekaiser, giving you both the Phantom buff (puts an enemy at 100 health, making them easy to one shot) and the Knight buff with Sejuani (making her harder to kill). I have seen several teams go all in on one specific synergy and lose because of it: I saw an all Blademaster comp fall flat because they literally went all Blademasters and nothing else. Blademasters can be decent, but it needs to have another Demon or an Imperial for Draven or something. Going all in on one type won't (and shouldn't, imo) win you the game. Even Nobles you typically run Phantom (Kindred+Morde) or Glacial (Ashe+Sej/Braum) or something alongside.
Thirdly, no matter how unlucky you are, you should try to avoid tanking your economy. You should never do more than one or two rerolls in a turn (maybe a few more if you're doing really well on money) and you should always try to end with 10+ gold for the extra interest (1 gold per turn can go a long way, more if you get to 20, 30, etc). There are a few instances where I think tanking your savings is worth it: maybe you got that sixth member for Nobles or something, a really great buff that is worth poring money into levels for. Stuff like that. Don't waste it looking for that 3 star unit, it will hurt you in the long run.
Lastly, I think the RNG serves to provide ways to test your adaptability and how you manage your bench and how you can CHANGE your tactics. The only instance of RNG I feel is unfair is the number of items: more items is just a flat out advantage that can't be gotten around via planning or adaptability, they are too essential and too strong for that.
All this blabbing is to basically say that I feel there are plenty of opportunities to strategize and come up with a "tactic". Sure, I can admit sometimes you definitely get screwed by the RNG, but you can also get lucky. And there are plenty of games where I'm somewhere in the middle. There have been times where I wasn't getting a unit I was going for, so I took the risk and shifted my composition away from that unit: often times it paid off, as I was able to get something else that synergized with what I had in a different way. If you don't like the game, that's fine, but I feel TFT is balancable and can be fun. There are some things that I've felt are too strong that they've already nerfed, and they will continue to adjust things as the Beta continues. The RNG of the items is something I'm praying that they finally do something about; that's pretty much the only instance of RNG I'm not cool with.
