I never have any trouble with hoppiness, so I can't add much to troubleshooting your issues. But, if you are using the right varieties in the right quantities, at the right times in the boil, then I agree with the others that you should look at your water composition. I can tell you how I do it....maybe this will help:
I use Tasty McDole's water profile for my IPAs:
Ca-110ppm, Mg-18ppm, Na-17ppm, SO4-350ppm, Cl-50ppm.
My own profile after adding salts to my local water is as follows:
Ca: 125
Mg: 17
Na: 12
SO4: 298
Cl: 51
HC03: 46
Tasty works with 100% distilled water. I make this using 50/50% carbon filtered tap water, and distilled water. Then I add epsom salts, gypsom, and CaCl. I add 1.5ml of lactic acid to the mash to counteract the HC03 and keep the mash pH at 5.5 (room temp). I cut with distilled because my local water is reasonably high in HC03, and for beers with an SRM below 10-12 I have trouble controlling mash, sparge, and ultimately boil pH. For stouts and the like I don't bother.
I cut my sparge water 50/50 as well, and acidify it to get a of ~5.6. This keeps my running from rising above 5.8, which ensures that my boil pH is ~5.6. Boil pH is pretty important for hoppy beers, because it significantly changes the hop character if the boil pH gets above 5.8. Some even say that hops are nasty if the boil pH is above 6.0.
I make a second addition of salts to the boil, so that the final mineral profile of the beer stays as listed above. My salt additions for the mash are designed to set the mash pH. My salt additions to the kettle are to set the flavor profile of the beer.
Hop character is driven by the Sulfate to chloride ratio of the beer. According to Colin Caminski (Master Brewer at Downtown Joe's) the useful ratio of SO4:Cl is 9:1 to 1:9. Reportedly, most peoples tastes are sensitive to a 10% change in SO4:Cl ratio. So, at the extremes that's a change of a full unit in the ratio. Tasty uses a ratio of 7:1, my profile has a ratio of about 6:1. That probably results in a subtle difference. The point being that you want to be heavily into the high SO4 range (not neutral or worse Cl >> SO4).
NOTE: You can use BeerSmith's water profile tool to calculate the needed salt additions for you. However, there is a bug in the tool:: It does NOT take into account any dilutions that you make. So if you do like I do, and cut your water with distilled...then BS2 will NOT calculate the salt additions correctly. For this and a couple of other reasons, I use the EZ Water spreadsheet, instead....it does EXACTLY what we need a water tool to do. It would be GREAT if beersmith could integrate the calculations that EZ Water makes....or even have a water tab that replicates EZ Water.
http://www.ezwatercalculator.com/
As a second way of looking at the problem, perhaps you could post the hop schedule for one of your problematic recipes? By way of example, my PtE clone hopping looks like the following:
90min 4.25oz Columbus (14%)
45min 1.25oz Columbus (14%)
30min 1.63oz Simcoe (13%)
------------------Flame out---------------------Steeping/Whirlpool hops to follow
30min 3.00oz Simcoe (13%)
30min 1.50oz Centennial (10%)
I add the steeping hops at flameout, give it a good stir, and let it sit at temperature (~195F) for 30 minutes. I lose over a gallon of wort to the mass of hops in the bottom of the kettle.