If this is the only reason you're dodging, I'd say to just fix queue dodging. Why is it a Dodge if you disconnect during champ select? It should only be a Dodge if you actually fail to select a Champion, or are not connected when champion select ends (maybe even wait 3 seconds to check if reconnected).
But you bring up a good point anyways, is an lp penalty for dodging really appropriate? The penalty is actually grossly inconsistent. In a promo series a Dodge is the same as a loss. When you're at 87+ LP (and are gaining the same for a win as you lose for a loss) a Dodge costs you basically nothing (you'll be in your promos if you win your next game regardless, or if you lose x win x+1). In general, if the penalty doesn't increase the time to a promo series it doesn't really do anything whereas of you're in promos or at 20/40/60/80 LP (assuming 20 per win/loss, obviously doesn't always apply) it costs you as much as a full loss.
In contrast, your larger time penalty idea would make the consequence the same regardless of where you are on the ladder. Perhaps only make that first Dodge not cost lp (you must play games before you can Dodge for free except for time penalty again).
