He was a really unstable character. He was above average at tactical and analytical inteliigence (imo ofc) but arrogance held him back, with that art obsession. And something people tend to forget is that he was heavily countered by Sasuke. At that point Sasuke's fight style was Basic Sharingan+Chidori streams with good use of the curse mark. Deidara had only 2 undeniable counters: dojutsu (being able to see c4 in the air) and lightning ( deactivating the clay).And he faced an opponent that relied on those two. I still think Kishi sacrificed Deidara in a non realistic way just to make Sasuke's power catch up with Naruto's. Same with Danzo. Anyway, I kinda got off topic. OT: Tactical and analytical intelligence, held back by character.