Unless you go with half step plus a granny gear, your gearing range will not be extended very much with just half step. In fact if you retain your high gearing, it might be lessened.

Having the large steps with the granny is usually welcomed (such as on a steep climb where you want a big gap to an easier gear). Tightened up range on the topside is also good and that's what the half step provides (for the flats/wind where the large gaps are not wanted and you still need enough gear not to spin out).

My trek runs a 50-47-26 with a 13-28 7 speed freewheel. The top two can half step down to a reasonable 45 gear inches, and when that's not enough I have five cogs between 41 and 25. It's a nice combo having 14 speeds cutting almost evenly between 103 and 45, every gear that it can run without extreme cross chaining is usable. I go all the way down to 25 because with friction shifting sometimes you need to back off a bit longer on climbs to get to the very low gears and it takes longer between gears than indexed setups. The 25 allows me to get going from almost a dead stop on hills.