i agree with you because the previous tests such as 86,92,97 were too taxing because the questions were too abstracted.
however, the questions in the 08 test do ask much clear questions to us. actually, today`s tests are much much far much easier than 08 test. (i did take the PGRE on 16,April,2016
but i don`t mention that you should abandon to solve and study the older tests.
they anyway contain a lot of valuable questions. by solving and studying the elder one, you will be able to get a clear understanding of the GREP test and you also will be able to get a lot of knowledge to solve GREP.
i recommend you to solve every problem in the samples and make the note to notice that which problems you could not solve or did not understand.
for example, if you have an incorrect answer in the problem number 1, you need to write down how to solve it in your note.http://grephysics.net/ans/all-solutions_list.php
here are almost solutions for the samples except 08 but you can find the solution for 08 on the internet.
* this is just my additional statement. if you have still a lot of time before taking the exam, it would be a good idea to solve the problems in the General physics book,such as Holiday, and Modern physics, such as Beiser. however, in this case, you need to focus on solving the problems which you often have made wrong answers in PGRE samples. for instance, i was really vulnerable to solve electromagnetism, especially Biot-savart law. in this case, i had found some problems which had to do with Biot-Savart law. after solving some problems,i started understanding how to approach and solve the Biot-Savart law.
anyway, good luck bro.