1. I'd argue Steamboat, but it's a real hard and potentially biased argument to make. The guy knew how to build a match, keep it interesting for the long haul, draw sympathy, and just be generally likable. It could be argued that Tanahashi possesses all of those same traits and has a more modern edge to them, but I think I'd give Steamboat the benefit of the doubt for having more of a power game to go along with his speed and agility. Tanahashi wrestles like a cruiserweight whereas Steamboat was a straight up rounder. There's also the fact that Steamboat could probably bust out half his offense from back in the day and give us a great match tomorrow if he got a wild hair to do so, whereas in some respects Tanahashi's skill is in decline with his age, or at least what brought him to the dance is, but he's still good and still adapting. It's a tough one, but I'll say Steamboat.
2. I'll say Tanahashi on the technicality that Steamboat was just being himself. There was no character. He was a family man who worked hard and acted humble. Tanahashi has a bit more dimension than that. He can be fun, he can be the stoic and unimpressed veteran looking to pull the best game out of a young talent he's gate keeping, or he can be exactly what Steamboat was. Point Ace.
3. Tanahashi. I was going to go for the excuse that Steamboat was bigger than Tana, but I just looked it up and the Ace has an inch on the dragon in height. Who knows how kayfabed that is, but there you go. In JCP, Steamboat might as well have been time traveling with the speed he had compared to pretty much anyone else, but Tanahashi has an extra gear in him I think.
4. Steamboat. The double chickenwing lift was something to behold. I don't think Tanahashi has anything that requires such static strength in his arsenal.
5. I'd argue tie. They're both mostly known for their crossbodies, and they both hit them beautifully with two different forms of the move. Outside of that, they really don't have much else. Sure, the High Fly Flow is both a crossbody and a frogsplash, but considering how similarly Tanahashi delivers both I'd argue it's splitting hairs to give him the extra point just because he does the same move from a different position.
6. I'd argue Steamboat. He had that southern brawling style that had to come across as believable. Flair's bumping definitely helped, but he also inherited a way snugger version of Flair's chops as well. I don't particularly think of either man as a striker, but looking back, heymakers and dropkicks were probably a bigger part of Steamboat's game than anything else.
7. I'll say Tanahashi even though they're both experts of the white meat babyface sell job. Tanahashi puts injuries out there to be exploited and plays them up for months. That's not only rare in Japan, but pretty damn rare in wrestling these days period.
8. Again, I'd say tie after "adjusting for inflation" so to speak. It's arguable that both men cultivated a reputation as storytellers and became the top of their respective promotions in their eras by displaying great storytelling and innovation within their styles.
9. Tanahashi. It goes back to Steamboat just being himself and Tanahashi being way more showy and playful.
10. I'd argue Steamboat because the guy was notorious for going broadway on the southern circuit.
11. Tanahashi. While Steamboat may have been the top babyface in the NWA, he was constantly booked to chase the gold and rarely win or hold it. Tanahashi held up NJPW's fort for sometime as the Ace of the company.
12. Back to this blasphemy. If I didn't make it clear before, I'm saying tie. The argument could be made that Steamboat's crossbody is the crossbody that all crossbodies are measured against, therefore making it the standard, but Tanahashi's standing High Fly Flow is a thing of beauty. Tie.
13. I will always contest Flair/Steamboat, but I do admit bias.