Israel has clearly a strong interest, as it's demonstrated by the number of times Netanyahu has called on the US to attack Syria (and he's of course cheering now that his wish has been granted). The reason? I'd say at least two. First, if you want to be a regional power, you need to be stronger than your neighbours (especially if they're not aligned with you). Which means that you need to have a powerful military and/or that your neighbour must be weak. And there's nothing like war and political chaos to weaken a country. Notice how many countries around Israel are either aligned with the USA (and therefore Israel) or piles of rubble.

Second, Israel already illegally occupies a portion of Syrian territory, the Golan heights. And has no intention whatsoever of giving it back. A torn country is the best way to make sure that the Golan Heights will never go back to Syria (which might not even exist anymore) (check [1])

The other reason I just found it in the news this morning, though it doesn't surprise me in the least. "Prime minister Netanyahu is pressing to ensure that any agreement that will end the war in Syria will include buffer zones on Israeli borders with Syria and Jordan. [2] " Now, we know what Israel does with "buffer zones". The West Bank is, technically, a buffer zone. They're just moving their own civilian population in it.

[1] https://www.google.nl/search?q=netanyahu+war+in+syria+golan+... [2] http://www.haaretz.com/israel-news/.premium-1.782143