Again. My bad. My wording wasn't exact. Here's my take: Shadow Dragon is not a bad starting point, but there are way better starting points.
You're right in that a lot of conveniences were added to Shadow Dragon. However, comparing Shadow Dragon to New Mystery of the Emblem (the sequel remake) is what makes me believe Shadow Dragon could have been more, which is my point. Shadow Dragon doesn't do enough to make you not think you're playing the first Fire Emblem game. In fact, I'd say New Mystery is a better starting point because of a more fleshed out story that really expands upon Shadow Dragon's world more than Shadow Dragon ever could, more interesting map layout, and tons of ways to play and break it.
Fire Emblem GBA follows Shadow Dragon's structures but provides way more in narrative and map designs and Fire Emblem Sacred Stones is comfortably easy and gives you a world map to walk around. All of this is said with the intent of making sure
@Mr. Wario gets the best pre-3DS experience so I hope I'm not coming off as aggressive or argumentative.
So in conclusion, Shadow Dragon is an okay starting point, but three other games I've listed adds more to it that help you get a better understanding of what classic Fire Emblem is like while still being incredible experiences. Those are my two cents anyway. Would you rather have more or less, Mr. Wario? I'll leave him with that.