disagree, for a few reasons.1. It's the handheld version of Smash, and I am honestly impressed with how much content they squeezed in to a multiplayer fighter on a handheld with, imo, outdated technology for a handheld gaming machine. Expect the Wii U version to offer a richer experience in terms of content simply because of the improvement of tech.
2. The single player I would argue is better than brawl. Brawl had a story and cutscenes, which were really cool, but I only touched Subspace Emissionary once. I had no reason to go back because there wasn't much left to do. The stickers were a cool attempt, but I think Smash Run/Equipment improved upon the system by making them more intuitive and usable outside a single mode. Smash Run in itself is a more repayable version of Subspace imo.
3. The stages I think were limited graphically, but I have enjoyed a lot what it has to offer. The new Kid Icarus, Fire Emblem and Animal Crossing stages are some of my new favorites, and I think having the option of a Final Destination version of each is a neat idea. I wish some had battlefield-like platforms, but it was a welcome attempt to appease competitive matches.
4. The roster is absolutely fantastic. I may not have had to unlock characters with the same, more intense requirements of melee, but that is fine. Let's say half the cast was locked and it took me 3 times as long to unlock everyone, and let's say one of them I REALLY wanted to play as. Once I unlock him, that would mean I arbitrarily "finished" the game and have nothing else to do.
For me the replay ability isn't just playing long enough or doing weird requirements to get characters. Don't get me wrong, I would have enjoyed it and would have liked some more characters to be hidden away, but I would not come close to calling the game boring simply because characters were available to soon.
5. Smash is a multiplayer game at heart, so basing the entertainment purely on the single player portion is a bit slanted I feel like? Almost all the content you unlock is designed to give you more tools and toys for you to use against other players or CPUS. To me just requiring grinding to unlock an item or character is not the only way to define value of a game. It helps, because I like seeking custom moves, but just adding more things to unlock I don't think is the magic answer
6. I am satisfied with the single player. Between Smash Run (minus points for not being online), kids Icarus uprising inspired Classic Mode, a plethora of unlock able moves/equipment/Mii costumes, multi-man smash, trophy rush, home run contest, target smash, and all star mode, I would say a lot of effort went in to keeping you occupied offline/by yourself. Yes I would have loved an Event Mode but I don't think for me that's a qualifier for the game being boring or not.
7. and finally, all the above has just described why the game is fun to me for single player, less than half the game. I am having a blast sky ping my friends and playing online, which at it's best comes very close to local play. I have spent hours winning or hating myself in For Glory 1 vs. 1, or I will take a break and fight on a team competitively, something I rarely did before they had a dedicated mode for that in Smash 4. I practice and test various custom moves to tailor my character to my style, to prepare myself for when I fight my friends in person or online.
Nintendo dropped the ball yet again, and this is not a 2014 online gaming experience.
And I feel this is subjective because I would say 75% of my matches are virtually lag free/limited lag when it come to 1 vs. 1. Even against people in Japan. Granted I live in a one bedroom apartment and my router is less than 20 feet away, but the online works great for the most part. Nintendo definitely did not drop the ball on this, they clearly saw their mistakes in Brawl and improved upon it fantastically. As opposed to Mario Kart or a shooter, lag is a lot more noticeable in a fighter, especially on a handheld, so the experience is not going to be seamless. I would say it's slightly lower quality than MvC3 online for the Vita (which is a stronger machine anyway)
All of these combined make Smash 3DS far from boring for me. Your reasons are valid, I am just curious if you are either missing out on huge portions of the game or simply just don't find value it them.