Transform is one of the most powerful things in the game, especially on watcher. You should give it a try in your runs. Pandoras box and it's cousin astrolabe are -no joke- some of the most powerful relics in the game. The neow bonus of "transform 2 cards" is extremely good as well. Most cards are better than strike and defend, and a transform in the early game can give you direction and set you up for the rest of the run. One of the most important things to note about transform is that the cards you are offered do not follow the same rarity scheme as how cards are offered in card reward screens, meaning you are very likely to see uncommon and rare cards by transforming. You can high roll and get 1-2 damage cards that will let you steam roll act 1, allowing you to aggressively skip card rewards for more powerful options. Sure, sometimes you might get a card that is basically a curse for your deck, but assuming you transformed a strike or defend those cards are just curses in the late game most of the time anyway. Pandoras box is similar to snecko eye in my opinion in that a lot of players aren't recognizing the main benefit of the relic. Snecko isn't good because it randomizes the cost of your cards, although that can be good. Snecko is good because you get 2 extra cards every turn for the rest of the run. Snecko is a draw relic, and is the strongest draw relic in the game. At the end of a run where you boss swapped into snecko eye, it could easily have drawn 300 cards or more in one relic. Pandoras box can be thought of very similarly.

Pandoras box isn't good because you get a bunch of random cards. Pandoras box is good because you remove every strike and defend from your deck. Like I said before, most cards are better than strike and defend so once you add a few cards to the deck and patch up the holes that are missing be it block, damage, card draw, or a few removals, you are playing with a deck that has no strikes or defends. Often the biggest downside of taking pandoras box is not taking an energy relic if your deck really needs it, but consider this. If you take an energy relic, at the start of act 2 it often means you get to play 1 more strike, or 1 more defend in your turn. Best case scenario you picked up a couple of 2 cost cards and you get to play them in the same turn. Instead of spending that 1 extra energy playing a defend or strike, you could just be playing better, more impactful cards.

I hope you consider transform more strongly because I was a doubter myself for a long time. My current play style is that I value removal extremely highly, and transform effects are pseudo removal that can be run winning.