On the topic of filler
I get where Gill and DeMarco are coming from when they say "not all filler is bad just like not all dubs are bad" and in that regard I have to agree. There are examples of filler done really well where if you didn't know better you wouldn't be able to tell it apart like InuYasha or Cardcaptors or series that are 99% filler using the manga/ln as a ground work to do their own thing like classic Sailor Moon, Trigun, or GitS SAC where some people even without nostalgia have preferred these versions to the original. Heck even mediocre filler endings like FMA 03 or Soul Eater have elements or ideas that I like a lot and in some cases I prefer the way the anime filler writers like how Medusa is finally defeated in Soul Eater anime vs the manga.
Of course there is bad filler, lots and lots of bad filler that over the years has certainly poisoned the well and lead to the bad reputation filler has with your average anime fan even when compared to other media. Whether by it's mediocre original story/characters, it's lowered animation/budget, it's blatant contradiction of established canon, or it's random insertion in the middle of another arc. One of the worst offenders are the anime original filler ending which frequently throw away much of what the story has established leaving many plot points unresolved or underdeveloped like Soul Eater or FMA 03. The one that annoys me the most especially in a block format like Toonami is the random insert filler in the middle of arcs like the Boss Luffy specials or the current Shippuden filler in Japan. When the audience is invested in a story arc and you randomly yank them away either for silly comedy fan service or some side story that has no impact on the fight/arc you just interrupted the audience turning hostile is something that should be expected. Even if the excuse is "well we want to save up budget for the big canon fights" I'd rather these types of filler come in between canon arcs then during an ongoing arc. Again there can be examples of this that work well like showing Ten Ten vs Temari during the Chunin Exams but these are sadly few and far between.
On the topic of the current Shippuden filler arc, I think in a vacuum where had I not watched other Naruto/Shippuden filler or read/watch other parts of the series it'd be okay. The problem is I have see other filler arcs and I have read other parts of the series where this arcs major problem of "same old shit" really hurts my ability to enjoy it. Someone being in a situation "just like Naruto" is by far the most over done trope in the entire series that had you watched all of the anime and filler up to this point has been done about 9 times up to this point. Combine that with Sora taking on the worst traits of Naruto and Sasuke and you've made a character most of the audience is going to hate but is expected to sympathize with and root for. I will say as a whole this filler arc has had some good action and the fights for the most part have been solidly entertaining heck that first battle between Naruto and Sora might be 2nd to only Sakura vs Sasori in terms of exciting animation. This certainly isn't the worst filler arc I've seen in Naruto but it's far from the best.