Having only just beaten Red in the past few minutes, I will say this. Red is hard. Very hard. Much harder than he was back in Gold/Silver/Crystal and as a youngster, I thought he was hard then, but he's much more difficult here. I had to use plenty of full restores and revives to win. The hail was irritating too, but it could be used as both an advantage and disadvantage.
This was my team at the time of defeating Red:
*pokemonelite2000 image removed* Snapper the Feraligatr (Lv.70)
"image removed" Webslinger the Ariados (Lv.70)
*pokemonelite2000 image removed* Hardboiled the Togekiss (Lv.67)
"image removed" Stumpy the Sudowoodo (Lv.67)
*pokemonelite2000 image removed* Bagheera the Umbreon (Lv.67)
"image removed" Tarzan the Primeape (Lv.70)
His Pikachu, which I didn't think was too much of a threat before is a powerful beast. Luckily, my Primape knew Close Combat, which took out Pikachu in one hit and thankfully didn't paralyze me on impact (like it did on previous tries).
The order he sends his Pokemon out vary and my tries all differed, but let's just do them in the order I recall battling him against.
Blastoise was next and he was fairly difficult to take on, since I had no Pokemon with Grass or Electric moves. With no clear advantage I sent out Umbreon (which with Red no longer owning an Espeon like he did in G/S/C, had no chance to dominate the battle) to whittle it down. It died pretty soon into the battle and its attacks hardly mattered when Red used his one of many full restores. If I remember correctly, I sent out a mix of Feraligatr, Ariados, Togekiss and Primeape to finish it off. Took a while, but it worked.
Charizard was next and this was pretty easy. Sudowoodo defeated it with one Rock Slide.
Lapras (which replaced Espeon) was a little difficult. Again, I think I weakened it down with several Pokemon, before sending out Primeape again to use Close Combat.
Snorlax has thankfully been made a tad easier without Rest, but he was still difficult and his HP took a while to take down. Using a few Pokemon again, before I sent out Primeape again with Close Combat was my strategy once again.
Venusaur was next and boy this was annoying. I tried to keep Feraligatr, Togekiss and Ariados alive for this battle. Red kept using full restores on Venusaur, much to my fury to the point where I wanted to throw a DS across the screen, but after some time, my Ariados (good resistance to its moveset) and Psychic were enough to end the battle.
And cue anti-climatic ending. Next time, I'm going to take the time to raise my Pokemon to a more even level. Next time Red, I shall kick your arse properly.