It has been done consecutively in the official games. Game Freak's starters have always been stronger than the average Pokemon. Their final evolutions end up having, at the lowest, 525 base stat totals I think, which is high relative to other Pokemon (excluding pseudo legendaries and legendary Pokemon, though they are legendaries). They tend to finish as some of the strongest regular Pokemon in the game. At least I wouldn't trade them off for another Pokemon in the wild, as starters have always been special -- in the official games, you never find them in the wild and are only received once every playthrough (with an exception to X & Y). So, picking some of the strongest (in the end) has been consistently done by Game Freak (though it can be argued that BSTs aren't everything in battle; they are still pretty relevant.) Basing off of the thread, the topic creator seems to prefer to use some of Game Freak's starters, which are all pretty strong and share around the same BSTs, but in the third generation, some of them have awful level up moves early on (i.e. Johto starters (which also are of one type), worse without a good availability of TMs) and would be extremely inconvenient if the hack is rather difficult.
Thinking about it a little more, I was basing that completely on the hacks I have played recently, of which tend to be on the higher side of difficulty, especially in the beginning. What I am thinking now: if you seek to make it difficult, I would go with the better starters rather than awful ones. If you do not aim to make it a difficult hack, any triangle is acceptable to me (Pokemon Bronze is the epitome if I say so myself -- the starters are average, but unique -- the hack stays at a nice difficulty all through out, making it so that it is beatable with more possibilities rather than only pseudo legendaries and Pokemon with immense defenses). But perhaps choosing awful starters can be a factor in making a hack more difficult as well, so completely up to the hacker. Personally, I am not the type who likes to level grind very often (I prefer progressing difficulty, where everything in the beginning isn't more difficult than the final challenges.)
Sinnoh starters are pretty fun as well, though you would have to insert them into the third generation games.