Well, do you have a heavy bioload? I ask because a wet/dry really isn't the ideal situation for a planted tank.
Wet/drys are great at rapidly converting large amounts of biological waste (mainly Ammonia) to less-toxic Nitrates, and at gas exchange/oxygenation. Both of these functions are important for tanks with a lot of Cichlids, or other messy fish.
In a planted tank, however, your plants should be capable of using nitrogen compounds, including NH4+ and NO3, directly, so can do most of your biological filtration better than a wet/dry. Some bacteriological processes are still necessary, but you don't need the huge, highly oxygenated surface area that a wet/dry provides. Plants also oxygenate the water.
See what I'm getting at?
You might consider modifying your sump. It can be used to hide your heater, diffuse CO2 (via the pump inlet, as mentioned before), and also to do mechanical filtration. For mechanical filtration - I'd suggest a prefilter stage - i.e. ceramic rings - for large particles, some foam for medium particles, and some poly fiber for small particles. You'd want to have all of this occuring fully submerged, and avoid trickling/splashing.
Does this make sense? I hope it helps.
Edit: I realized I wasn't clear on this - the biggest drawback of a wet/dry in a planted tank is that the massive gas exchange will make it impossible to maintain CO2 concentrations much higher than ambient. Even without the wet/dry, you'll be wasting a lot of CO2 to the flow of the water through the compartments of your sump. You'll have to make a conscious effort to minimize gas exchange in every component of the system. The one component you can't do much about is the overflows -- CO2 will be outgassed in the standpipes, plumbing (tubes/hoses/pipes), and in the first compartment of the sump. Luckily, you'll be re-carbonating the water before it is returned to the tank, which is about as good as it gets. Good luck!