Slow cloth would require the bigger stroke and would reward the players with the power. It would do more to separate the quality of players. The thick cloth was one thing the IPT probably had right. We all love to play on slick cloth, you can get most anywhere most of the time, thick cloth not so easy unless you got the power.
Some rules which would make an interesting high level format
Slow Cloth, 4.5" pockets, 10 ft table, 2 shot foul count on the cue ball not the player , 9 ball, rack it on the spot, small break box, winner breaks, jump ok with full length play or break cue.
that would definitely be interesting and quite a challenge to even the best players