Having something that increases costs causes an unknown rules issue... if you play a Lion with a Highway in play, does Copper cost
or
? There is no right answer; different people will look at it and play differently. Highway reduces Copper to
, and Lion makes it into
. Or, does Lion make it into
, and then Highway brings it back to
? Bridge Troll is Donald's way of doing a cost-increasing attack; it makes other players take their -
token. That works similarly to increasing the cost of things.
Also, since Lion increases costs for yourself as well; it's pretty weak. The cost-increasing effect basically just balances out between you and your opponents, so all you are really getting is the next-turn draw, and the reaction thing. The next-turn draw is worse than
Hunting Grounds, for the same cost.
And as a terminal; it could be quite difficult to ever take advantage of the reaction thing. You would need to play a village, then play Lion, then play an attack, and then your opponent would have to choose to reveal a reaction. Though of course it would work better with reactions such as
Tunnel.
But then you have other weird things, like what if you make them reveal a card using something like
Spy or
Cutpurse, and the revealed card is a reaction, maybe
Moat, or maybe just
Tunnel. A reaction was revealed so I guess they should trash it; as worded. But it also says they follow the effects.
I don't see a reason to have it say "they follow the effects". You don't need to specify that; that's just what happens normally when you reveal a reaction. Telling them that they trash it later shouldn't cause anyone to think that they don't still do what it says.
And what about reactions like Horse Traders? That doesn't get revealed when used. So Lion wouldn't affect it? Also, there's a tracking issue; the reaction is hidden away in their hand, so how can they be forced to trash it? What if they used something like
Secret Chamber, which may or may not leave the reaction in their hand afterwards. If it isn't in their hand, it can't be trashed.
Basically, I just don't see how either part of this card can work. The cost-increasing is better done with a -
token, and the reaction-trashing thing just has far too many rules and wording issues to work.