Keep in mind that loft degrees is only one factor in how far you will hit these irons. You really will not know your gaps until you hit them. You may find that dropping the highest iron and adding their 48 degree still gives you distances you are used to and the gap between the T150 48 and the Vokey 50 might still work fine. I personally would go that way or change Vokey to 52/56/60 before messing up the factory lofts on a full set of T150's.

Although Titleist does not publish their bounce angles the concensus on various forums is that Titleist bounce angles are lower than most manufacturers so I don't think adjusting loft up to 2 degrees with a corresponding increase in bounce angles will be an issue. as far as turf interaction. The increase in loft will also reduce offset so may have some influence on your ability to square the club at impact, but, it may not be significant, particularly if squaring the club head isn't an issue currently. Also if the look of less offset appeals to you the more likely the change in bounce angle won't be a factor for you.

It may be a good investment to have a professional look at your swing for some thoughts as to whether there are any swing characteristics (e.g. Angle of Attack) you have that may suggest that the increase in bounce is a bad idea for your game.