wet saddle pads (ie hours in the saddle) or active training sessions (where you are challenging your horse to learn). Anyone have an opinion?

Not sure what you mean here, but I'll take a stab at it. If your saddle pad gets wet from exercise, that's just part of the deal. Just like our shirts get wet when we work out. Never feels good at the time, if you even notice it. The showers sure feel good afterwards though.

Some horse just naturally sweat more than others. If your trying to get a horse in shape or working cattle, riding on the beach for pleasure, what ever the cause. It really doesn't matter. Some younger horses may be impatient and need to be learn to be patient, does not necessarily have to be done under saddle. Every horse is different, like people. They all learn at different levels or speeds. Personally, I hate seeing any horse under saddle for hours, especially young horses. But in some cases it may be necessary, each case is different.

What is the situation you are referring to?

Oh boy.

Circlek... Wet saddle pads without the "challange to learn" or without practicing newly learned things do not make much sense to me.

Well, if a horse is stabled or penned most of the time, the purpose would be just plain exercise - which might be a good thing.

But wet pads in my opinion do not excluded training or practicing more than plodding along. I worked with a friend for many years on cows. The horses sure got their share of miles chasing cows. But that did not exclude that we would do things like side passing coming off the mountain. Though I sometimes was sure that some day campers were thinking "drunk cowboys" seeing horses going sideways down a little road.

Combination would be my answer.

GC

I think the time you spend with your horse both in and out of the saddle will help build the bond between you, and help you ride better.

What is your answer to your own question?

Training-hands down.
Example- Go look @ a 10+/- sale horse.
The thing is barely more than green broke, yet an unknowledgeble owner keeps telling you how wonderful it is.

Of coarse how well a horse is trained is all relative the the person using it.

I'll take a good training session over filly farting around anyday.

GC- Has mentioned the most important detail. Training never consists of ring work only.