1. Feudalism is actually not that useless as most ppl seen...Although in order to use it precisely would require mastering knowledge to the game itself, or at least, all the cards in the game. The icon is not bad either, 1 leaf on that card can be quite handy in some situation say preventing someone from doing machinery on you. Yea that card is a bad splayer but it work in harmony in some cases, say you are going alchemy and requires a bit more castle(splaying left on base cards with castle would always give a castle), or cases that you want a domination on castle. Of course you can use it to set up a paper streak too.
2. Actually among the base set the most heretic card is the socialism in age 8. Very weird card, although it is not useless either. If, in a 2 player game where both players are not developing super boards, going for score and achievements and have few icons, an age 8 purple card with 3 leafs can be a tire-breaker for leaf dependent situation. You cannot find such a card with pure leaves on a purple until you are back in age 4(reformation). The weird usage of socialism is not useless either. Being shared a satellite from your opponent where you meld socialism and tuck empiricism and grab the hand of your opponent, hence shut him down from the last part of a satellite. Weird enough.
(Lighting in age 7 gives 2 leaves and 1 clock, which sounds good but it is subject to the wicked Skyscraper in age 8 which you may lose everything due to it, while a pure leaf card in age 8 like antibiotics and socialism is basically intact from most crown dependent demand cards such as banking or enterprise or socialites. The only potential threat is the good old Compass back in age 3. The good thing about this is if what you only want is a age 8 top card for an achievement, all you want is a secure card without being threatened. Yea mobility can crush both of them and kick you plain hard, but mobility is tough to deal with anyway)
3. Suburbia is no-where a weak card...Being 1 action knock out from a Fermenting-Reformation-Suburbia and you will know why. Why bicycle if my opponent is not working on anything emergent?
4. And actually IMO bicycle is way more weird than suburbia. It is not a real scorer nor a real winner, which requires you so much action to execute. Without a massive hand you cannot generate a huge amount of score. But even so bicycle is still extremely handy, giving you some of the most weird options available, such as storing the score on your hand in-order to prevent score invading tactics(e.g. Mass Media, Combustion, Rocketry, etc.) and grab your last achievement after you set it all up.
5. I can still add a lot others...though this is a lot already.