I haven't played Magic since it first came out, for exactly the reason you point out. I had no interest in turning a fun, casual game into...well, whatever you're calling "professional" Magic.
There's no reason Magic can't be casual. Most games I play are.
Likewise, I have no interest in playing whatever kind of D&D it is that wouldn't be described as "casual." I'm playing the game for fun, not...uh, bragging rights? (Why exactly are you playing, if not to have fun? Someone will have to tell me.)
Again, I'm not saying that you shouldn't have fun, but we should at least acknowledge that some things you do in the game are worse than other things. WotC has admitted that they made some choices deliberately weaker than others.
Just because Twilight sucks as a work of literature, for example, does not mean it is a bad thing to read and enjoy it. Not everything book has to be on the level of Tolkien... but we should at least admit to the flaws in Twilight even if we are on Team Edward. (Which, incidentally, I am not. I have always preferred werewolves. I mean, Edward's a pasty emo whiner and Jacob's just this gorgeous tanned hunk...)
Then why didn't I? I played this character in a "CR appropriate" campaign for long enough (8 levels) that these alleged performance issues surely should have appeared, and yet they didn't. I can assure you the DM didn't pull any punches, and I doubt I was extraordinarily lucky overall.
Weren't you using 40 point buy? That's as much as four tens. And that's
terrible.
In all seriousness, though, the book recommends either the elite array for PCs or 28 point buy for "high powered" games. You had 40 point buy. That's 12 more points than 28 point buy, from a mathematical perspective. That's a lot of points above "high powered". Do you think that might have affected things any?
But if you want to evaluate the build here, we can do that. How do you want to do it? Choose a CR 6 monster from a list of CR 6 monsters? That's considered a reasonable encounter for a solo character by the book.
[sblock]Annis (hag): 2 claws +13 melee and bite +8 melee
Baleen whale: tail slap +17 melee
Belker: 2 wings +9 melee and bite +4 melee and 2 claws +4 melee
Bralani (eladrin): +1 holy scimitar +11/+6 melee or +1 holy composite longbow +11/+6 ranged or slam +10 melee
Chain devil (kyton): 2 chains +10 melee
Demon, babau: 2 claws +12 melee and bite +7 melee
Digester: claw +11 melee
Megaraptor (dinosaur): talons +9 melee and 2 foreclaws +4 melee and bite +4 melee
Ettin: 2 morningstars +12/+7 melee or 2 javelins +5 ranged
Gauth (beholder): eye rays +6 ranged touch and bite -2 melee
Girallon: 4 claws +12 melee and bite +7 melee
Half-black dragon, 4th-level human fighter: masterwork two-bladed sword +10/+10 melee and bite +5 melee, or 2 claws +10 melee and bite +5 melee, or javelin +5 ranged
Hydra, five-headed cryo-: 5 bites +6 melee
Hydra, five-headed pyro-: 5 bites +6 melee
Hydra, seven-headed: 7 bites +10 melee
Lamia: Touch +12 melee, or dagger +12/+7 melee and 2 claws +7 melee
Monstrous centipede, Gargantuan: bite +11 melee
Salamander, average: spear +11/+6 melee and tail slap +9 melee
Shambling mound: 2 slams +11 melee
Skeleton, advanced megaraptor: talons +9 melee and 2 claws +4 melee and bite +4 melee
Tendriculos: bite +13 melee and 2 tendrils +8 melee
Will-o'-wisp: shock +16 melee touch
Wyvern: sting +10 melee and bite +8 melee and 2 wings +8 melee and 2 talons +8 melee
Xill: 2 short swords +5 melee and 2 claws +5 melee, or 4 claws +5 melee, or 2 longbows +4 ranged
Xorn, average: bite +10 melee and 3 claws +8 melee
Zombie, gray render: bite +16 melee or slam +16 melee[/sblock]
Or we could go with a CR 7 monster, if you think that 40 point buy increases your character's power by enough to warrant it.
[sblock]Aboleth:4 tentacles +12 melee
Animated object, Gargantuan: slam +15 melee
Black pudding (ooze): slam +8 melee
Bulette: bite +16 melee and 2 claws +10 melee
Cachalot whale: bite +17 melee and tail slap +12 melee
Chaos beast: 2 claws +10 melee
Chimera: bite +12 melee and bite +12 melee and gore +12 melee and 2 claws +10 melee
Chuul: 2 claws +12 melee
Criosphinx: gore +15 melee and 2 claws +10 melee
Dire bear: 2 claws +19 melee and bite +13 melee
Dragonne: bite +12 melee and 2 claws +7 melee
Drider: 2 daggers +3 melee and bite +1 melee, or shortbow +5 ranged
Elasmosaurus (dinosaur): bite +13 melee
Elemental, Huge (any): 2 slams +19 melee (air and earth), 2 slams +17 melee (fire and water)
Elephant: slam +16 melee and 2 stamps +11 melee, or gore +16 melee
Formian, taskmaster: sting +10 melee and 2 claws +8 melee
Ghost, 5th-level human fighter: incorporeal touch +6 melee (+8 against ethereal foes), or masterwork bastard sword +10 melee, or masterwork shortbow +7 ranged
Giant, hill: greatclub +16/+11 melee or 2 slams +15 melee or rock +8 ranged
Golem, flesh: 2 slams +10 melee
Hellcat (devil): 2 claws +13 melee and bite +8 melee
Hydra, eight-headed: 8 bites +11 melee
Hydra, six-headed cryo-: 6 bites +8 melee
Hydra, six-headed pyro-: 6 bites +8 melee
Invisible stalker: 2 slams +10 melee
Lillend: short sword +11/+6 melee and tail slap +6 melee
Medusa: shortbow +8/+3 ranged, or dagger +8/+3 melee and snakes +3 melee
Monstrous scorpion, Huge: 2 claws +11 melee and sting +6 melee
Naga, water: bite +7 melee
Nymph: dagger +6 melee
Ogre barbarian: +1 greatclub +16 melee or javelin +6 ranged
Phasm: slam +12 melee
Remorhaz: bite +13 melee
Skeleton, cloud giant: Gargantuan morningstar +18 melee or claw +18 melee or rock +8 ranged
Slaad, red: bite +11 melee and 2 claws +9 melee
Spectre: incorporeal touch +6 melee
Succubus (demon): 2 claws +7 melee
Umber hulk: 2 claws +11 melee and bite +9 melee
Vampire, 5th-level human fighter: slam +11 melee or +1 spiked chain +13 melee or masterwork shortbow +9 ranged
Yuan-ti, abomination: masterwork scimitar +13/+8 melee and bite +7 melee, or masterwork composite longbow +10/+5 ranged[/sblock]