Blizzard currently has no plans to increase the gold cap in Wrath Classic.
Someone asked the devs on the official forums if they had plans to increase the gold cap in Wrath Classic. Unfortunately, they think increasing the gold cap would not be healthy for the game at this point. The full response is included below.
While gold is definitely more plentiful from quests, dailies, and other sources in Wrath Classic, we don’t really feel like raising the gold cap would be healthy for the game at this point. We’ve been looking at gold data across all characters and also across all level 80s, and in general even the 100th percentile average (among level 80 characters in particular) is nowhere near the gold cap. We’ll keep an eye on it and may revisit this if we start seeing averages across the high-90’s percentiles start to bump up against the cap but we aren’t very close to that point and the cap that is in place is likely still appropriate.