Hey there!
Yeah always nasty when that happens. How much money was in the pot, and for how much more you went all-in, And you're opponent's Stack-size is also of importance in such a scenario. Example:
Pre-flop pot= $3.20
On Flop you go all-in for= $4.00
Opponent has $1.10 left, (so you're $4.00 raise is only a $1.10 call to him.)
$3.20+$1.10=$4.30 That's about a 4-to-1 Call for your opponent who has 9 outs x4 = 36% To hit
100/5=Break-even= 20% Conclusion: [Good Call]
Just to point that aspect out to you

But We'll just consider that you are both Deep Stacked in such a situation.
There is indeed not really a reason to push All-in in my opinion at least. You can make a bet of about 75%-100%. If you pick the pot up now, FINE. If he calls you're even happier because he made a mistake. Besides.... if you're very certain he's on a flush-draw. You're not going to pay him of if another Club comes up right?
Also I don't see why you should bet just half-pot on the Turn (if the Turn-card unlikely improved his hand.)
If he is a bad enough player to call a Pot-bet or 2/3 pot-bet just make another one. His mistake will be bigger and you're gains will be larger. Because like you said yourself you're not gonna pay him if another club come up.
Hope this is usefull to you, if not just post
