We've been speculating in the forums about the changes in the value of several item types. The most obviously influenced are tier 6 materials:
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Check a few of those links - you'll see prices climbing. A detailed post over on the reddit subforum by user rawrgs indicates that these changes are supply side - and the most popular theory in that thread is that a bot ban Wave is the cause.
Players report seeing fewer (to the tune of almost none) bots in the most prolific botting area: Southsun Cove.
Right now profiting from this isn't going to be easy. It's not something you can predict in the short to medium term (I'll get to long term in a minute) because we won't know (unless Anet announce it) that there is a bot ban wave incoming.
Now as for long term: I'm put in mind of a post I did a week or so ago - Learning To Make More Money in Guild Wars 2 - and I'll tell you why.
The knowledge or awareness that bots have an impact on the economy is something you can draw on to make long term predictions. You combine your in-game know-how with real world knowledge.
In-game; "I know that Tier 6 mats are cheap because of bots even though they are in demand," RL; "I know that Arenanet take a firm stance against botting but often take a while to take action. When they do take action it's on a large scale."
Working from here you can draw up a rough formula of sorts for long term investments in and around bot-saturated markets.
If you know (through following news sources or personal experience) that bots are in an area where (for example) a particular item, or group of items, drop in abundance and you also know that the demand for these items is pretty steady (but brought down by a large, botted supply), then you could purchase a sizeable supply of these items over a few weeks.
You might just benefit from the next bot ban wave.