Maybe it's a matter of semantics, but I'd prefer a reason to play a hand rather than an excuse. When you need an excuse to do something, that implies the action would normally be considered incorrect but you've rationalized doing it anyway. We can use implied odds as an excuse to play a lot of substandard hands, but most of those will end up being losers.
I have no problem trying to get in cheaply with suited connectors in late position, or better yet raising with the possibility of taking down the pot right there, but what's your plan when limping early and getting raised by a later-position player? Do you toss them, or put in the extra money with a speculative hand knowing you're probably an underdog unless you hit the flop hard?
In other words, what's your reason for playing QJs in early position? Do you think you have the current best hand? Do you think everyone else will fold? Are you just hoping to get lucky? Especially if you're limping, you're saying you hope to get lucky on the flop. That's not going to happen frequently enough to make up for the times you'll lose, unless you have great reads on your opponents and super ninja bluffing
56s is far worse than QJs because it lacks high card potential and can be more easily beaten by higher flushes. Its only benefit is that if it hits, its strength will usually be well disguised.
Here are a few good reasons (not excuses) to play speculative hands:
a) You're in late position and can get in cheaply, especially in a multiway pot.
b) You're in late position and the blinds are likely to fold to your raise.
c) You're playing your opponents, not your cards.
d) You just know that flush is coming.
What kind of tournaments are you playing where limping is common late in the game? With antes in play there's added incentive to raise preflop.