Rick....I'm certainly not an expert but it sure doesn't sound like a thatch problem to me. More likely some of the new growth didn't make it through the winter. What type of grass did you seed with last summer? Pics (if possible) would certainly help the very knowledgeable forum members (I'm not one of them) make a very good diagnosis with recommendations to you....

What kind of grass do you have? Certain types of grass do NOT take well to de-thatching. Some years ago, the theory spread that every year, if you wanted a beautiful lawn, you needed to de-thatch your lawn or have someone do it. Unfortunately, for people with grass varieties that spread via stolons (runners), this can cause more damage than any potential benefits. Let us know what type of grass you have; then, I would recommend taking a sample core so that you can measure the actual amount of thatch that you have in your yard.

Well, perhaps me being suspect of lawn crews. Here's my thoughts; When dethatching your lawn would have left very little of the debris you mentioned on the lawn, particularly twigs. But, depends on what you call twigs, vs. my version of twigs right? Dethatching is deep raking process. If done by machine, the small branches and pine cones would be broken up more than what you saw before they did it. If they did it with a tow behind, you would seen a good deal of it piled by the mower turn areas, because the tines would generally push the twigs rather than shred, then sweep it out in the process of the turn. In general, you should see a marked thinness of the turf as compared to before. This would be immediate after the tines hit and it's raked.

Here's what you can do to encourage bermuda. These are in order of importance. Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall. Mulch mow at the mower's lowest setting 2x per week. Relative to what reeljake said, I think the turf is mature enough to mow low now. Fertilize monthly through the growing season with a high N (low to zero P and K) fertilizer. If you want to get your soil microbes going, fertilize with an organic fertilizer in addition to the monthly chemical ferts. I like alfalfa pellets (rabbit chow) and/or corn meal at 15-20 pounds per 1,000 square feet. If you want to get a soil test, skip the TAMU test and get the $25 test from Logan Labs. Post your results here for a good analysis showing what to apply, why, when, how often, where to get the stuff. You can soften your soil by applying any clear shampoo at a rate of 3 ounces per 1,000 square feet. Try to stick a screwdriver into it and get a feel for how hard it is and how deep you can push. Do that when it is dry and when it is moist. Then 3 weeks after you sprayed the shampoo, do that screwdriver test again. If you're not happy, spray it again. Shampoo is the most effective way to soften the soil. Is your soil surface perfectly level with no humps, bumps, or holes? If not you might want to level it this summer. We can help with that.