^Well, a perfect card to me means that it does it job perfectly, not that it is perfect at every moment during the game. I get what you're saying about not being able to build a deck around Pachirisu, but it still does its job almost to perfection. However, I have a few things to say about this Pikasquirrel...
I'm quite surprised at all the hype this card has gotten. I mean, I recognize it as a great card, but most of its comparisons are to SS Dunsparce. Let's look at the history of "Basic-grabbing Basics" with this game. Dunsparce was an amazing card that found its way into nearly every deck. If you didn't have 4 slots open for it in your deck, many would say that you didn't have a deck. When Dunsparce rotated, everyone turned their eye to DX Plusle, another Basic that could grab you more Basics with a second attack that was amazing. However, the entire strategy for getting Basic Pokemon into play soon changed with the addition of one particular card: Holon Mentor. With Holon Mentor essentially doing what Dunsparce could do, who wouldn't run it? Why risk running Plusle if you could just throw in Mentor and get started with your main Pokemon (or something else to set you up)? Look at the typical MetaNite build of last season. Did you see any Plusle in those decks? Any Lanette's Net Search (the "Corsola" of Basic-grabbing Supporters)? Nope, you saw Mentor with a good starter that didn't get Basic Pokemon -- Holon's Castform.
The thing is, Pachirisu is overshadowed by the existence of Holon Mentor. Yes, it's true that Mentor isn't as powerful without Holon Transceiver, but with 4 in your deck you're still leaving yourself with plenty of room to focus on Basic Pokemon that can help you set up in different ways... Pokemon such as SW Mew, Stantler, Baltoy, etc. The reason I'll put Pachirisu in my deck, however, is because of its second attack. Smash Short is basically a Windstorm in the form of a Basic Pokemon (with the exception of not being able to get rid of Unown G). With the absence of such things as Cessation Crystal, I've wanted to drop Windstorm from my deck altogether. Pachirisu lets me do that, since I can always rely on it to knock off those pesky Cessation Crystals if I need to. Since it's a card that can be recycled back into my deck, it's great both early game and late game. So though Pachirisu's first attack isn't all that much to look at, its second attack certainly is, warranting at least 1 spot in most decks as a tech.
I'll give it a 7 out of 10 in the current modified format. Not all decks will even use Pachirisu, but most decks will tech at least 1 in because of its second attack. If you don't go up against any Pokemon Tools that need to be done away with, however, Pachirisu probably won't even hit the field.