The amount of episodes stands at 16 at the moment I believe not including the 45 minute pilot 'movie'. I have not watched what there is of the second season yet. However, it is not as though this "stupid little series" is standing on its own. It is held up on the shoulders of The Lion King itself. With returning characters (and in a few instances returning voice actors) this show resonates well with people who have seen or grew up with The Lion King. This would mean the parents of quite a few of the toddlers and young children currently who would then be more than happy to put this on the television in favour of another show (I'm looking at you, Dora). It also helps that this series is legitimately good. The children they got the voice act (and let's all be thankful that they got children and not a multitude of female voice actors that can "pass off" a child's voice because, let's face it, while passable it's not entirely convincing (looking at you Timmy Turner)) have talent. The music included in the show (1 song per episode) is generally well written with no songs that could be considered legitimately bad and with others that are quite outstanding (Sisi Ni Sawa, for one). Harking back to the point about parents preferring this show on the television to others due to nostalgia, this is more evident in the animations of the characters (oh yes, the age old "the animation is good!" argument returns - however with a twist). In the animations are references to the Original lion king. For example, in Sisi Ni Sawa the two characters for a moment do the iconic Hakuna Matata head flip as they walk, or in another instance Simba and Nala, while singing, do the iconic back to back pose from Can you Feel the Love Tonight. etc etc. While not standoutisih enough to beg attention, there are little nods to the giant on which this series stands.
All this to not even touch on the writing of the show, the messages that the show is trying to convey (which, in my opinion, are not as blatantly "here's your sign" as almost any other young children's show out at the moment) and the fact that they have proven that they're not afraid to touch on darker topics such as death. All of which give this show a more mature air and weighty feel. Of course everyone is entitled to their opinion and some argue - with very well thought out points - that this show is ruining Lion King - or less doomsdayish, at the very least changing it. As to their correctness and at which level they are correct, i say figure it out for yourself.
If this post reads very defensive it's because I was getting kind of defensive - not gonna lie. However, that's not really my point. I really just want to point out that a series doesn't have to have grand origins or a multitude of seasons backing it up to become big. Let's take a look at Firefly here. As long as they show stays true to itself and doesn't try to become too much or something that it is not, in most cases it will prevail.