Im not sure about training a whole season of IS, but certainly this season, you would want to be doing at least a couple of weeks of either IS, or 1n1 for forwards.
if you did that over the next 3-4 seasons, you would get your 3-4 IS pops.
With regards to IS on a PG, there is a fair bit of debate going around, so this is just my opinion (which I will back up with stats).
Go look at the FG% of guards on the transfer market. Use a filter to filter those with IS Less than Medicore, and those with IS greater than Mediocre. Assuming most play at PG/SG, you will find that the greater the IS, the greater the FG%. This is because IS is related to inside shots INCLUDING layups
BUT has a greater influence for things like dunks/putbacks/shots in the key. Because he will be a PG, he won't take as many dunks/close range shots that PF/C will. But driving layups. definately. i think this is the point which some people will disagree, but just use the numbers you find from the transfer market to decide for yourself.
So in general, for a PG, IS being atrocious = bad. IS being medicore = not bad. IS being Strong or above = awesome.