No you can't!
Yes they can.
None of the others can trash any card in hand AND gain any card in the supply costing up to $3 more than the trashed card. The others are all restricted in various ways. Tsk tsk.
They also don't cost $7 and more or less suck horribly. Hell, Mine is generally considered to be a weak $5 card. It's not that any of them is rigorously strictly superior to Expand in literally every possible way... it's just that if I'm looking for Expand to do anything in particular, it's horribly outclassed at it in that particular case. Unless you reeeeeeaaaally want to turn Gardens into Forges or something... who the hell knows.
That's a bad argument though. First of all, the card that does the specific function better might not be on the board. Second, Expand might be beat at a specific thing by another card, but it still does things that card can't do.
Let's consider Masquerade for a second. If you want the draw, Courtyard gives you better selection. If you want the trashing, Chapel lets you trash more. If you want to pass junk to other players, Ambassador means you don't receive any junk back. Man, Masquerade sure is outclassed in every way!
Seriously though, Expand usually isn't good, but I don't think it deserves so much hate. Plus it has really sweet card art.
Your examples aren't even in the same ballpark, though. None of those cards can do what Masquerade is good at, though Ambassador is a close call - all it's missing is a two-card draw to filter through stuff. And Ambassador is a strong $3 card. Mine costs $5, and is usually sort of weak - mind you, Expand costs $7.
Mine is a lot better than Expand if you want treasure -> treasure. There is no reason you'd want Expand if Mine is on the board for this, and "Mine might not be on the board" doesn't make Expand not suck. Similarly, Rebuild blows Expand out of the water if you're going for VP - it's non-terminal, and it finds the VP for you (unless you drew them all, but ok). Want to trash junk cards? Altar still costs less, ties when trashing Estates, and is strictly better at trashing coppers and curses - like, by a lot. Half the time, Expand is just a regrettable Upgrade in my hand that should've been a Gold.
I honestly don't know what he was thinking when he made Expand cost $7. It might be strong at $5 or weak at $6, but at $7, it's the Scout of TFB cards, hands down. If I started the game with Upgrade and Expand in my deck, I'd be more inclined to Upgrade my Expand for a Province than vice versa.
. Only makes Provinces cost 4
