Yes, I think it is time for a 4" model. I hope SYK will sell it with a sheath. If not, I'll pass. All knives that require a sheath for carry should be sold with one that fits it properly. A nice little kydex would be perfect for a 4" knife, but a well made cordura or leather would be fine with me. The 4" to 5" blade knives are very useful. I hope it is not over 3/16" thick.
Amen brother, though I appreciate the custom leather & kydex sheaths I do not like spending 50% to the full price of the knife on a sheath unless it is safe queen. I have only 1 or 2 of those, the rest I use and cheap well fitting pants is all I need.