Just like any game its up to the GM on how big a deal it is going to be. Some dungeons and dragons game groups have no rogue. Some sword and sorcery game groups have no sorcerer. Obviously they will have to work on getting around the problem in new and inventive ways or have the GM insert some useful tool or NPC to pick up the slack.
While I certainly agree with the former posters that hacking is much more integrated in SR4 I did want to say that I have seen it slow down many a gaming group. There is a great deal of information on that link. You need to decide about every slotting person they might encounter and what that person has on their link. Most folks say that there is simply no pay data on the link, or if their is something important thats what you get, but so much data is contained therein that an imaginative hacker (or a real world IT guy) is going to have a lot of legitimate points about the type of data on that link that can be useful. For example that random guy you thought was important but wasn't... where does he work, what does he have access to, what kind of hobbies does he have, does he have a family, where does he live, whats his SIN, what kind of car does he drive, who's link #s does he have, whats his bank account #, does he have any bad habits you find out about? Much of that is straight up pay data if its sold to the right person(s) and also can lead to all manner of other chaos.
Another concern is the depth of hacking you want to do. Getting into a link is just the beginning in many cases. There is dodging IC, dodging spiders, getting into connected nodes and/or devices and how to manipulate objects to get what you want. Is it encrypted, is there a data bomb, more IC, hidden nodes, etc. ? Then there are agents to deal with and how they can degrade based on the node they are going into.
Personally I like hacking a lot but unless the GM and I are both on the same page, I am either way to much trouble or every person's link is rating 6 or higher with multiple IC to match. Or the reverse is true and the players get into the link but have no idea what they want to do there or how to do it.
Generally I consider the lack of a archetype a kind of a free pass in my games. I can build barriers that they need great inventiveness or special people to overcome or I can drop troublesome elements from the game where I basically just build as part of the story. Such as worrying about enemy hackers that should be trying to use the same dirty tricks on the runners that they are using on the target. My favorite mechanism to date is to have a free AI take up residence in the runner's link. Provides a great mechanism for role playing plus helps the runners and the AI. Another option is that one of the runners can get a few more nuyen in the initial runs as the team "hacker" he can run a agent or two that have a variety of hacking skills. If they don't want to deal with any of the hacking you already have the agent's stats and you can figure it out as needed if the agent is able to do what they need.
Even though it is pretty unreasonable that any professional team could get by without a hacker, there are always alternatives. In the end you just have to make your game work the way thats fun for you and them, with or without a hacker.
