Scion said:
Nah, simple math

and lets not ignore items.
No doubt about it. You can get more defensive items than offensive items.
But, you have to survive to do that and the vast majority of opponents at all levels will not have a boatload of these types of items in most campaigns (otherwise, the PCs will quickly acquire them). A first level Sorcerer with +4 DC Daze can help out his party immensely compared to the Sorcerer without that +4. The one with the feat has a much better chance of survival.
His DC goes from 13 or so to 17 or so and most non-spell casters will not make that save. Even most spell casters will only make it 30% to 50% of the time.
Scion said:
Looking at the table for what bonuses can do what none of them list dcs while 7 list saves. +5 resistance, +5 insight, +5 luck. It may be a lot of money, but it is nothing for the levels we are talking, and that is +15. The +3 from the stat item just doesnt even come close. There are still 4 other bonuses to choose from for more bonuses as well.
Let's be realistic. How many of these items actually exist in the core rules and how many actually make it into the hands of PCs (or NPCs for that matter) in most campaigns? Sure, a DM can introduce new items of these types to his game, but there are only a few in the actual DMG (3E rules):
Potion of Heroism, +2 to saves, 900 GP (single use per potion, has to be activated)
Staff of Power +2 to saves, 200,000 GP (nearly impossible to obtain until real high level)
Candle of Invocation +2 to saves, 7800 GP (easy to blow out, knock over, etc.)
Cloak of Resistance +1 to +5 to saves, 1000 GP to 25000 GP (the main contender for defensive items)
Horn of Goodness/Evil +2 to saves, 6000 GP (only against evil if good, good if evil, no powers if neutral, does not stack with Cloak of Resistance)
Pale Green Ioun Stone, +1 to save, 20000 GP (does not stack with Potion of Heroism)
Robe of the Archmagi, +1 to saves, 75000 GP (does not stack with Cloak or Horn)
Robe of Stars, +1 to saves, 58000 GP (does not stack with Staff of Power)
Stone of Good Luck, +1 to saves, 10000 GP (does not stack with Robe of Stars or Staff of Power)
So, if you just HAPPENED to have the right combination of these items (Potion of Heroism drunk, Staff of Power, Candle of Invocation burning, and +5 Cloak of Resistance), you could beef your save up by +11 (not +15).
But is that even close to reality for the vast majority of opponents in the vast majority of games? Are crafting or acquiring +5 luck bonus items when there isn't so much as a single +3 luck bonus item in the DMG reality for most games? Not for any competent DM that I've ever encountered.
Typically the high level Sorcerer will have his +6 (i.e. +3 to DC) CHA item and his opponents MAY once in a blue moon have as high as a +5 Cloak of Resistance. But even a +5 Cloak of Resistance merely takes a characters weak save types up to the same level as his strong save types at high level.
And if the NPC opponents have +5 Cloak of Resistances, that means that soon all of the PCs will have them as well. The DMs I have played with might only introduce one of them to an entire campaign for NPC opponents (and that would probably be for the greatest NPC reoccurring villain).
The Sorcerer, on the other hand, gets the +4 DC to certain spells at level one (which straight out counters a +4 Cloak of Resistance) with Sorcerers Pact. A 16000 GP item nullified at first level.
Right off the bat, no magic items required. Everyones a winner. No blanks.
And, btw, the reason that Damage Reduction and Spell Resistance exists for monsters is so that they cannot be one shot destroyed and once destroyed, the PCs cannot take those protections away from them and use them for themselves.
Scion said:
Immunities are pretty easy to gain as well for that matter.
Uh, where?
Not at low to mid level to my knowledge.
Sure, there are some spell resistance items and some spell turning items, but those should be extremely rare as well (i.e. most NPC opponents will not have them) and low to mid level opponents will rarely if ever have them.
You are really stretching by discussing magic defensive items. Not only are there not that many of them, not only do not that many NPC opponents have them (in most campaigns) enough to offset +4 DC, but none of that really matters with regard to the issue of whether Sorcerers Pact is broken anyway.
Wizards do not get feats that give +4 to DC. Why should Sorcerers when Sorcerers already can cast more spells per day (and hence, have more spells to cast when one fails)?
Magic items are basically non-sequitor to the issue of the power level of Sorcerers Pact. If they are prevalent enough to become so in a campaign, then the campaign is already Monty Haul and you might as well introduce overly potent feats. What's another +4 DC when your PCs have +15 or more worth of save protection already?
