Transom mounted rudder makes it harder to steer (especially in strong wind when going upwind) compared to all other types of rudders. That can be counteracted to some degree by reducing sail area and having a long tiller. I have a 20 foot boat with transom mounted rudder (Mirage 5.5m) and that is my observation. I made a longer tiller for it, which was a very easy job. Some people make an extension to their regular tiller, which they put on only in rough weather, so there is more room in the cockpit.
Certainly the helm may feel "heavier" on an outboard rudder, but that is purely a result of the unbalanced nature of the rudder. Some would prefer to say the outboard rudder has more "feel". Weather helm is a completely different problem. Weather helm is when excessive rudder ANGLE is required to keep the boat from rounding up. It has nothing to do with whether the rudder is transom mounted or not. It has everything to do with sail trim, rig tune, heel angle, etc. If anything, theoretically, a transom hung rudder would be more powerful than the same rudder hung under the boat because it is a greater distance from that fulcrum that is the keel so it provides a greater mechanical advantage. (Of course there will be those that would argue that the outboard rudder loses efficiency because it doesn't have the bottom of the boat providing an "end plate" effect.... but we won't go there!)
There are a great many high performance boats that use outboard rudders, and I can guarantee you that they don't suffer from any kind of weather helm inherent to the rudder design! Look at the J-24; if anything they suffer from chronic LEE helm and they have outboard rudders!
More practical considerations:
My last boat was a race boat with an outboard rudder, and that allowed me to remove my rudder so that I didn't have to put antifouling on it. I just stowed the rudder below! If your rudder gets damaged, you can remove it for repair with the boat in the water.
If your rudder gets fouled with seaweed or a crab trap line you can easily see it and clear it. On a rudder hung under your boat the rope could get jammed between the top of the rudder and the hull, requiring a swim to clear.