Good music.

Good artwork, like xxBKxx mentioned, screen caps from tv shows are just the suck.

Good lightshows for significant events (HS2 jackpot and super jackpot come to mind).

Video modes are optional but if there is one then amalgamate it into the game objectives (eg: freeing doctors in DW)

Skill shots that require actual skill (eg shoot for the trunk in TOM), not just advance lane until the light is under the ball drop.

Clear view of all playfield targets and toys, it sucks when features are hidden from view of the player.

I like conditional mini pf / games that are tucked away until activated, like in Doctor Who, Pinbot, Mousin' Around.

Multiball.

Fun ramps and wireforms - ones that playfully wiggle, zig zag, loop, etc. Ie, not just a straight up, over, straight back down.