Was the Vilna Gaon correct in opposing Hassidut? Is Hassidut an acceptable philosophy?

Almost all new movements come to stress a true ideal that was previously being neglected. On the other hand, most new movements also take their positive innovation to an extreme, often at the expense of another important aspect. Rav Kook wrote that the Vilna Gaon, in his time, had to oppose the hassidic movement in order to “balance” out the negative aspect which arose there, e.g. the belittling of the centrality of Torah study, laxity regarding times of prayer etc. On the other hand, Rav Kook writes that it was inevitably just a matter of time until the positive Hassidic stress on happiness and kabbala complimented (!) Torah study. Today, the Hassidim learn a lot of Torah and the Yeshiva world has adopted most of the Hassidic ideology, as well (it’s even hard to differentiate between them!). In short, we must always take the positive aspect stressed in each Jewish ideology, and leave the negative (“speaking against” some other aspect) aside. Harmony is based upon the beautiful balance between the different tones. Similarly, history is comprised of: thesis, anti-thesis, synthesis. “Lag” Same’ach!