Various articles have been written bemoaning the death of Test cricket, too many to even bother linking to. Just as many articles have been written in support of it, pointing out the most recently completed thriller as an example of how the format is awesome and must not be killed.
Test cricket is unique among the 3 forms of the game in that there is an option for an honorable draw. THAT is what sets it apart from T20 and ODIs. And for every thumping win that a team has, there is a gut-wrenching draw or near-draw to fall back upon. This was never better illustrated than the recent two Test series between Sri Lanka and England, where Sri Lanka nearly lost the first one but held on for a draw and nearly drew the second one but hung on for a win.
Mark Nicholas said it best in the article linked above. Here's an excerpt from it (I strongly urge you to read the whole thing to get a taste of the drama):
Now if you wanted to slag off Moeen, you damn well could. I mean, fancy not nicking the strike to save Jimmy from himself (Joke.) Jimmy, Jimmy, Jimmy. Balls 51 to 54 were superbly handled. Two remained to save the match, a task incidentally that no other team in history that had been five down going into the last day of a Test had achieved.
Eranga sprinted up the Headingley hill. He flung the leather short and hard at Anderson's throat. If only Anderson had ducked, or swayed, or slipped, or fell. But he didn't. See Moeen, Jimmy tried to play this frightening missile with his bat, or glove, or hand, or wrist or something. From his bat, it ballooned up in the air and was caught. If it had been you Moeen, no problem. You are a marvellous batsman. Whereas Jimmy, if not quite a rabbit, is no Geoff Boycott. The best nought in the history of cricket came to nothing, whichever way you look at it.