I would suggest a decrease in half for reward paired with an increase length for block rewards:
example:
16 coins / 3 months
8 coins / 6 months
4 coins / 12 months
2 coins / 24 months
1 coin / 48 months
This will help bottle neck the high influx of coins for the short term while still preserving long term mining efforts.
I´m sorry, that doesn't work:

How about this: Add a 32 coin block reward step and it works out much better. I think this transition holds an advantage over a constant 18 month time interval for block rewards. The coin needs a well thought out bottleneck in current production that also doesn't kill mining in the future. Let's be realistic, unless smartcoin is an extremely valuable coin down the road, no one will ever mine it for a .0001 SMC block reward. Adding a 32 coin block reward in the mean time might be a good idea as well; smartcoin mining might die all together if the block reward drops to 16 at current prices.
Reward Blocks Month New Total
400000 1 0 400000 400000
1 2-999 0 998 400998
64 1000-111000 2 7040000 7440988
32 200000 5 6400000 13840988
16 400000 11 6400000 20240988
8 800000 23 6400000 26640988
4 1600000 47 6400000 33040988
2 3200000 95 6400000 39440988
1 6400000 191 6400000 45840988
0.5 12800000 383 6400000
52240988 * mining capped at 51.2M leaving a mining time table of ~30 years