Nah, Szeth isn't a great swordsmaster himself. Can't be. As a regular Shinovar citizen he was not allowed to fight/train for fighting and once he had become truthless I doubt that he had a swordmaster. He beat men in shardplate by chucking big rocks at them until their armour was crushed and by lashing people to the ceiling until the light ran out and they fell to their death. He also used his height advantage by being airborn.
And you have to consider, that a freaking 2 meter two handed sword handles a lot like a pole weapon, at least part of his pole weapon training is useful for him in terms of his shardblade fencing, particularly the reflexes (parrying is a lot about automated reflexes, you see the thing coming and without thinking you hold something in the way so it doesn't hit you, that's something intense spear training will prepare you for, because the trick is the automated reflex, not the type of longish object you hold in the way). Actually, in an airborn shard duel, the spear is really a good weapon, because the longer reach compared to a sword means you can hit the opponnent while he can not hit you. Also a shard-spear will not break, so you can parry with it as long as you watch your fingers (the lack of a crossguard makes it dangerous, but then, the deadspren shardblades were not used in man to man combat where you need a crossguard, but to slaughter big monsters, so probably a lot of them do not have one)
The most satisfying parts? Where Shallan and Adolin have that romantic dinner, he starts rambling about his military accomplishments and she just asks him what happens when he an urgent need while he is on the battlefield. That scene had me rolling on the floor.
When Elhokar was put in his place by that Herdazian matron. My goodness, the immature whining of that guy had been getting on my nerves the entire book, and the FINALLY....
When Adolin killed Sadeas. Yeah, will probably have repercussions, but was well worth it. One irresponsible, egomaniac a-hole less on that continent.
Of course, Kaladin rescuing the Kholins at the battle of the tower.
Jasnah Kholin, for her sheer awesomeness, that she dares to openly be an atheist, defying the ridiculous Vorin religious beliefs.