I hear what Nethula means with white ball in future. We play very less test cricket for a starter. To bowl in test cricket, you need to toss it up, rip the ball, look for the drift and turn. It's a lot of work and truck loads of overs in training to come close to mastering that. Besides you can't bowl **** balls these days, they just disappear. Easier route is to be like Zampa, bowl quicker through the air, have some variations, you don't have to turn heaps and bowl hard length. Far easier to master and don't need to bowl forever to work this out. Besides you still get to play to a full stadium, more followers and way more income. Besides you play way more white ball cricket as well in comparison to test cricket so opportunities are way more.
As soon as you say a promising young leg spinner, I generally wait up to see how they'll go in the long run. If there is growth sprout and the lad grows tall then the loop is going to be gone. Ideal to be shorter in stature to get the flight and dip but tall leg spinners can also bowl all right. In NZ though you have to bowl into the pitch rather than give it the air and try to beat by flight. The surface doesn't grip and skids so a flighted good length ball is dispatched square of the wicket on these decks. If he plays for ND then he has a reasonable chance to develop as that is one deck that surely does aid spin bowling.
What I've seen generally from my helping out leggies and spinners is they start to rely on the flipper or toppies way too much. Besides they will be asked to bowl quicker through the air and soon enough they lose the ability to flight the ball. Really depends on the coaches and captains that can trust spin bowling. Ravindra is a good example of this, saw him bowl in u19s and he had a fantastic flight, beat the batters in the flight and turned the ball from different angles. I've been watching him of late, he never bowls bad but he bowls 2 or 3 over spells as if he's bowling at 180k and needs to rest after 2 overs. If you end up with a captain like we have at Firebirds, kiss the spinner good bye. I can't remember Ravindra bowling more than say 2-3 overs in a spell. I check this whenever any spinner is bowling around the country and I see the trend is quite normal unless it is Ish, Santner, Ajaz or Somerville bowling. Rest of the spinners are just there to make up numbers I feel.
I see that in Kane as well, he's so reluctant to use spinners at home. Canterbury with Cole as captain is managing the spinners very well I see. He still trusts to bowl himself and Theo Von W as wicket taking options. I like that.
Ashok may be very good but really depends on the coaches and the captains to get him better in the long run. In general our spin bowling coaching knowledge is very low to minuscule at grass root levels. Was watching Sheffield on sky and couldn't help noticing how much more smarter those captains are with their spinners. The Under 19 Aussie spinners couple of years ago, Pope was bowling and was bowling quite **** but they kept bringing him back consistently. Over here a spinner goes for a four or couple of fours he's done...